In vitro evidence that hyperglycemia stimulates tumor necrosis factor-α release in obese women with polycystic ovary syndrome

in Journal of Endocrinology
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  • 1 1Department of Reproductive Biology and
  • 2 2Department of Medicine, Schwartz Center for Metabolism and Nutrition, Case Western Reserve University School of Medicine, Cleveland, Ohio 44109, USA

Women with polycystic ovary syndrome (PCOS) are often insulin resistant and have chronic low-level inflammation. The purpose of this study was to determine the effects of hyperglycemia in vitro on tumor necrosis factor (TNF)-α release from mononuclear cells (MNC) in PCOS. Twelve reproductive-age women with PCOS (six lean, six obese) and 12 age-matched controls (six lean, six obese) were studied. Insulin sensitivity (ISHOMA) was estimated from fasting levels of glucose and insulin and percent truncal fat was determined by dual energy absorptiometry (DEXA). TNFα release was measured from MNC cultured under euglycemic and hyperglycemic conditions. ISHOMA was higher in obese women with PCOS than in lean women with PCOS (student’s t-test; 73.7 ± 14.8 vs 43.1 ± 8.6, P < 0.05), but similar to that of obese controls. ISHOMA was positively correlated with percent truncal fat (r=0.57, P < 0.04). Obese women with PCOS exhibited an increase in the percent change in TNFα release from MNC in response to hyperglycemia compared with obese controls (10 mM, 649 ± 208% vs 133 ± 30%, P < 0.003; 15 mM, 799 ± 347% vs 183 ± 59%, P < 0.04). The TNFα response directly correlated with percent truncal fat (r=0.45, P < 0.03) and ISHOMA (r=0.40, P < 0.05) for the combined groups, and with plasma testosterone (r=0.60, P < 0.05) for women with PCOS. MNC of obese women with PCOS exhibit an increased TNFα response to in vitro physiologic hyperglycemia. MNC-derived TNFα release may contribute to insulin resistance and hyperandrogenism, particularly when the combination of PCOS and increased adiposity is present.

Abstract

Women with polycystic ovary syndrome (PCOS) are often insulin resistant and have chronic low-level inflammation. The purpose of this study was to determine the effects of hyperglycemia in vitro on tumor necrosis factor (TNF)-α release from mononuclear cells (MNC) in PCOS. Twelve reproductive-age women with PCOS (six lean, six obese) and 12 age-matched controls (six lean, six obese) were studied. Insulin sensitivity (ISHOMA) was estimated from fasting levels of glucose and insulin and percent truncal fat was determined by dual energy absorptiometry (DEXA). TNFα release was measured from MNC cultured under euglycemic and hyperglycemic conditions. ISHOMA was higher in obese women with PCOS than in lean women with PCOS (student’s t-test; 73.7 ± 14.8 vs 43.1 ± 8.6, P < 0.05), but similar to that of obese controls. ISHOMA was positively correlated with percent truncal fat (r=0.57, P < 0.04). Obese women with PCOS exhibited an increase in the percent change in TNFα release from MNC in response to hyperglycemia compared with obese controls (10 mM, 649 ± 208% vs 133 ± 30%, P < 0.003; 15 mM, 799 ± 347% vs 183 ± 59%, P < 0.04). The TNFα response directly correlated with percent truncal fat (r=0.45, P < 0.03) and ISHOMA (r=0.40, P < 0.05) for the combined groups, and with plasma testosterone (r=0.60, P < 0.05) for women with PCOS. MNC of obese women with PCOS exhibit an increased TNFα response to in vitro physiologic hyperglycemia. MNC-derived TNFα release may contribute to insulin resistance and hyperandrogenism, particularly when the combination of PCOS and increased adiposity is present.

Introduction

Polycystic ovary syndrome (PCOS) is one of the most common female endocrinopathies, affecting 4–10% of reproductive-age women (Knochenhauer et al. 1998, Dunaif 1999). The disorder is characterized by hyper-androgenism, chronic oligo- or anovulation, and polycystic ovaries, with two out of these three findings required to diagnose PCOS (Rotterdam Group 2004a, 2004b). As many as 70% of women with PCOS exhibit insulin resistance, with the compensatory hyperinsulinemia considered to be the cause of the hyperandrogenism (Burghen et al. 1980, Nestler et al. 1998, Goodarzi & Korenman 2002, Rotterdam Group 2004a, 2004b). In addition, women with PCOS are often obese, a condition strongly associated with insulin resistance and hyperglycemia (Kolterman et al. 1980, Ciaraldi et al. 1981).

Hyperglycemia can contribute to the development of insulin resistance and impaired insulin secretion in a phenomenon known as ‘glucose toxicity’ (Rossetti et al. 1990, Yki-Jarvinen 1992). It is recognized that these effects may be the exaggeration of normal regulatory responses to increases in circulating glucose. We have shown that in PCOS, hyperglycemia causes an increase in reactive oxygen species (ROS) generation from peripheral blood mononuclear cells (MNC) (González et al. 2006). ROS-induced oxidative stress is a known activator of nuclear factor κB (NFκB), a proinflammatory transcription factor that promotes tumor necrosis factor-α (TNFα) gene transcription (Barnes & Karin 1997, Mohanty et al. 2000, Evans et al. 2002). TNFα is an established mediator of insulin resistance (Hotamisligil et al. 1994). Thus, increased TNFα release from MNC in response to hyperglycemia may be an underlying mechanism for insulin resistance in PCOS.

In vitro studies have shown that TNFα can truncate insulin receptor signaling in all insulin-sensitive tissues (Feinstein et al. 1993, Hotamisligil et al. 1994, Del Aguila et al. 1999). In obesity-related diabetic syndromes, TNFα is overexpressed in adipose tissue and causes increased serine phosphorylation of insulin receptor substrate-1 (IRS-1) (Hotamisligal et al. 1993, 1995, Rui et al. 2001). This leads to decreased expression of GLUT 4, the insulin-sensitive glucose transport protein (Stephens & Pekala 1991). Insulin resistance in PCOS is also a post-receptor defect, and increased serine phosphorylation is implicated as the cause of decreased insulin-stimulated IRS-1 activation and decreased GLUT 4 expression (Rosenbaum et al. 1993, Dunaif et al. 2001, Li et al. 2002, Corbould et al. 2005). Thus, the ability of TNFα to stimulate increased serine phosphorylation makes it an ideal candidate for initiating these molecular events in PCOS.

We have previously reported that circulating levels of TNFα are elevated in PCOS (González et al. 1999). A likely source of excess circulating TNFα in obese women with PCOS is adipose tissue, but the source remains unknown in lean women with the disorder. MNC are known to migrate into adipose tissue to activate adipocyte TNFα production (Weisberg et al. 2003, Wellen & Hotamisligil 2003). It is now clear that the major source of TNFα in adipose tissue of the obese is MNC-derived macrophages present in the stromal-vascular compartment (Weisberg et al. 2003, Xu et al. 2003, Fain et al. 2004a, 2004b). Thus, MNC may be an additional source of excess circulating TNFα in PCOS.

In the present study, we evaluated an in vitro model of hyperglycemia to determine the effect of direct exposure to hyperglycemia on TNFα release from MNC of women with PCOS. We hypothesized that TNFα release from MNC is increased in women with PCOS compared with weight-matched controls in response to hyperglycemic conditions, and that there is a relationship between measures of adiposity and MNC-derived TNFα release.

Materials and Methods

Subjects

Twelve women with PCOS (six lean and six obese) aged 21–34 years and 12 weight-matched control subjects (six lean and six obese) aged 20–38 years volunteered to participate in the study. The women with PCOS were diagnosed on the basis of oligoamenorrhea and hyper-androgenemia after excluding nonclassic congenital adrenal hyperplasia, Cushing’s syndrome, hyperprolactinemia and thyroid disease. Polycystic ovaries were present on ultrasound in all subjects with PCOS. All control subjects were ovulatory as evidenced by regular menses and a luteal phase serum progesterone level greater than 5 ng/ml. All control subjects exhibited normal circulating androgen levels and the absence of polycystic ovaries on ultrasound.

All subjects were screened for diabetes or inflammatory illnesses, and none were taking medications that affect carbohydrate metabolism or immune function for at least 6 weeks prior to study participation. None of the subjects were involved in any regular exercise program for at least 6 months before the time of testing. All of the subjects provided written, informed consent in accordance with the Case Western Reserve University and Metro-Health Medical Center guidelines for the protection of human subjects.

Study design

All study subjects underwent the oral glucose tolerance test (OGTT) on days 5 and 8 after the onset of menses. Before the OGTT, they were provided with a healthy diet consisting of 50% carbohydrate, 35% fat and 15% protein for 3 consecutive days (days 1–3) before the test. The test was performed on the morning of day 4 after an overnight fast of ~12 h. All subjects also underwent body composition assessment on the same day the OGTT was performed.

Oral glucose tolerance test (OGTT)

Fasting baseline blood samples (5 ml each) were drawn for glucose and insulin determination. A 75 g glucose beverage was subsequently ingested over 10 min. Blood samples (5 ml each) were again drawn for glucose and insulin determination 2 h after glucose ingestion. Upon completion of the test, subjects were fed a high-carbohydrate snack. Plasma glucose concentrations were assayed immediately from the blood samples collected. Additional plasma was isolated from the fasting blood samples and stored at −70 °C until assayed for C-reactive protein (CRP) and TNFα. Glucose tolerance was assessed by the WHO criteria with normal glucose tolerance defined as a 2-h glucose-stimulated value less than 140 mg/dl, impaired glucose tolerance as a 2-h value of 140–199 mg/dl, and type 2 diabetes mellitus defined as a 2-h value of 200 mg/dl or greater (Modan et al. 1989). Insulin sensitivity was estimated by ISHOMA by the following formula (Matthews et al. 1985): fasting glucose × fasting insulin/22.5.

Body composition assessment

Height without shoes was measured to the nearest 1.0 cm. Body weight was measured to the nearest 0.1 kg. Waist circumference was measured at the level of the umbilicus and used to estimate abdominal adiposity (Kohrt et al. 1993). In addition, all subjects underwent dual energy absorptiometry (DEXA) to determine percent total body fat and percent truncal fat with the QDR 4500 Elite model scanner (Hologic, Waltham, MA, USA). Truncal fat content was defined as the area between the dome of the diaphragm (cephalad limit) and the top of the greater trochanter (caudal limit) (Taylor et al. 1998).

Analytic methods

MNC isolation and culture were performed on a 20 ml fasting blood sample drawn before ingestion of the glucose beverage during the OGTT. The cells were isolated by Histopaque-1077 density gradient centrifugation (Boyam 1968), washed two times in pyrogen-free saline, re-suspended in RPMI (0.3 mg/ml l-glutamine, 100 U/ml penicillin and 100 μg/ml streptomycin) with serum substitute TCH, and seeded in coated culture plates (2.5106 cells/ml). The culture medium was supplemented with d-glucose at varying concentrations to mimic a euglycemic (5 mM) or hyperglycemic (10 or 15 mM) environment. The cells were incubated (humidified, 5% CO2, 37°C) for 24 h. Cell supernatants were subsequently collected (10 000 g for 2 min) and stored at −70 °C until analysis. Plasma glucose concentrations were measured by the glucose oxidase method (YSI, Yellow Springs, OH, USA), while plasma insulin concentrations were measured by double-antibody RIA (Linco Research, St Charles, MO, USA). Plasma CRP concentrations were measured by high-sensitivity ELISA (Alpha Diagnostics International, San Antonio, TX, USA). TNFα concentrations were also measured by ELISA (BioSource International, Camarillo, CA, USA). All samples from each subject were measured in duplicate in the same assay. The interassay and intra-assay coefficients of variation for all assays were 7% and 12% respectively.

Statistics

The StatView statistical package (SAS Institute, Cary, NC, USA) was used for data analysis. The difference in values under either hyperglycemic condition (10 or 15 mM) and the euglycemic baseline (5 mM) for primary dependent variables, such as TNFα release from MNC, was calculated to represent the incremental change. Descriptive data and the incremental change of variables were compared between groups by unpaired Student’s t-test or ANOVA for multiple-group comparisons followed by post hoc analysis. Differences between the incremental change of variables within groups were analyzed by paired Student’s t-test. Alterations in TNFα release from MNC within groups were expressed as the percent change between either hyperglycemic condition (10 or 15 mM) and the euglycemic condition (5 mM, 100% baseline). Differences in the MNC-derived TNFα response among the different glycemic conditions within groups were analyzed by repeated-measures ANOVA. Regression analyses used the Pearson (r) correlation for parametric data and the Spearman rank order (ρ) correlation for nonparametric data. All values are expressed as means ± s.e.m. An α-level of 0.05 was used to determine statistical significance.

Results

Age and height were similar among groups (Table 1). Weight, body-mass index (BMI), percent total body fat and waist circumference were significantly (P < 0.01) greater in obese subjects than in those who were lean whether or not they had PCOS, but were similar when women with PCOS were compared with weight-matched controls. The obese also exhibited significantly (P < 0.01) greater percent truncal fat than lean subjects whether or not they had PCOS. However, percent truncal fat was significantly (P < 0.02) greater in lean women with PCOS than in lean controls.

Circulating levels of LH, testosterone and androstenedione were significantly (P < 0.05) higher in women with PCOS than in control subjects independently of body weight (Table 2). Circulating DHEA-S levels were modestly higher in women with PCOS than in weight-matched controls. Levels of glucose while fasting and 2 h after glucose ingestion were similar in women with PCOS to those of controls independently of body mass. All 12 control subjects had a normal glucose response during the OGTT with 2-h glucose levels of 62–138 mg/dl. Glucose values at 2 h were consistent with impaired glucose tolerance in two lean women with PCOS (141 and 148 mg/dl) and one obese woman with PCOS (192 mg/dl). Fasting insulin levels were modestly higher, and plasma CRP levels were significantly higher (P < 0.05) in the obese whether or not they had PCOS (Table 2). CRP levels were also modestly elevated in lean women with PCOS compared with lean controls.

ISHOMA was significantly (P < 0.05) higher in obese women with PCOS than in lean controls and lean women with PCOS (Table 2). Lean women with PCOS exhibited an ISHOMA that was similar to that of obese controls and lean controls. ISHOMA was positively correlated with BMI (r=0.58, P=0.004), percent body fat (r=0.49, P < 0.02) and percent truncal fat (r=0.57, P < 0.004) for the combined groups (data not shown).

TNFα release from MNC under euglycemic conditions (5 mM) was similar in women with PCOS compared with controls (Table 3). After exposure of MNC to hyperglycemia at the 10 mM glucose concentration, the incremental change in TNFα release of women with PCOS increased significantly (P < 0.03) compared with that of controls, which slightly declined (7.0 ± 3.3 vs −2.9 ± 2.2). When subjects were grouped by body mass, the incremental change in TNFα release from MNC exposed to 10 mM glucose increased significantly in obese women with PCOS compared with either lean controls (P < 0.005) or obese controls (P < 0.05). In contrast, the incremental change in TNFα release from MNC of lean women with PCOS was similar to lean controls after the 10 mM glucose exposure. There were no significant differences in the TNFα response of women with PCOS compared with control subjects regardless of body weight after exposure of MNC to 15 mM glucose.

The percent change in TNFα release from MNC in control subjects remained unchanged under hyperglycemic conditions (10 mM, 103 ± 20%; 15 mM, 136 ± 33%) compared with the euglycemic condition (5 mM, 100%). In contrast, the women with PCOS exhibited a significant (P < 0.02) progressive increase in the percent change in TNFα release from MNC under hyperglycemic conditions compared with the euglycemic condition. The MNC-derived TNFα response to hyperglycemia was significantly greater in women with PCOS (10 mM, 410 ± 124%, P < 0.03; 15 mM, 541 ± 200%, P < 0.05) than in controls. When subjects were grouped by body mass, lean controls exhibited no difference in the percent change in TNFα release from MNC under hyperglycemic conditions compared with the euglycemic condition (Fig. 1). Obese controls and lean women with PCOS exhibited a modest increase in the percent change in TNFα release from MNC in response to hyperglycemia compared with lean controls. However, there was a significant increase in the MNC-derived TNFα response to hyperglycemia in obese women with PCOS (10 mM, P < 0.003; 15 mM, P < 0.04) compared with either control group.

After exposure of MNC to hyperglycemia at the 10 mM glucose concentration, the percent change in TNFα release from MNC was positively correlated with BMI, percent truncal fat and ISHOMA for the combined groups, and with BMI for women with PCOS (Table 4). The percent change in TNFα release from MNC was also positively correlated with androstenedione for the combined groups after exposure to both 10 and 15 mM glucose, and for women with PCOS after exposure to 15 mM glucose. The percent change in TNFα release from MNC and testosterone were positively correlated for women with PCOS after exposure to 15 mM glucose, and negatively correlated for controls after exposure to both 10 and 15 mM glucose.

Discussion

Our data clearly show that in vitro exposure to hyperglycemia causes an increase in TNFα release from MNC of obese women with PCOS. The in vitro conditions demonstrate that the enhanced TNFα response is directly related to hyperglycemia, and occurs at a glucose concentration similar to the postprandial state (10 mM) or higher (15 mM). The TNFα response is directly related to the degree of insulin resistance and to the levels of androgens. Since TNFα is a proinflammatory cytokine, these findings provide further support for the role of inflammation in the development of insulin resistance and hyperandrogenism in PCOS. TNFα, in particular, may contribute to the decline in insulin action in obese women with PCOS. Furthermore, the association of TNFα with BMI, percent total body fat and percent truncal fat suggests that the combination of PCOS and increased adiposity may be a key determinant of the MNC-derived TNFα response observed in obese women with PCOS, and its potential role in inducing insulin resistance in these individuals.

Hyperglycemia within the physiologic range does not result in increased TNFα release from MNC in normal circumstances. Lean controls in the present study exhibited no change in MNC-derived TNFα release in response to either hyperglycemic culture condition. This is in contrast to a previous report of increases in TNFα release from MNC of normal individuals exposed to hyperglycemia in vitro (Morohoshi et al. 1996). In this study, however, the glucose concentration required to achieve this response was above the physiologic range. Since TNFα is a known mediator of insulin resistance (Hotamisligil et al. 1994, 1995, Del Aguila et al. 1999), the lack of increase in TNFα release from MNC may be a physiologic benefit in the presence of hyperglycemia. Thus, facilitation of glucose disposal in lean controls may be due to the control of TNFα release to optimize insulin signaling in the postprandial state.

In contrast, the MNC of obese women with PCOS have increased sensitivity to hyperglycemic conditions in the physiologic range. Obese women with PCOS are in a proinflammatory state, as shown by the elevations of plasma CRP observed in this group that are consistent with previous reports (Kelly et al. 1996, Bastard et al. 1999, Yudkin et al. 1999). MNC-derived TNFα release increased in response to either hyperglycemic culture condition in obese women with PCOS compared with obese controls. Oral intake of glucose, lipid and protein has been noted to elicit similar proinflammatory responses in vivo (Mohanty et al. 2000, 2002, Aljada et al. 2004). It is possible that in obese women with PCOS, feeding results in increased TNFα release from MNC in the postprandial state to promote the insulin resistance observed in these individuals. This concept is supported by the positive correlation between the TNFα response and ISHOMA. Previous reports of a reduction in oxidative stress and inflammatory mediators after caloric restriction in the obese, and after a 2-day fast in normal subjects provide further corroboration (Dandona et al. 1998, 2001a, 2001b).

Our data suggest a link between adiposity and MNC-derived TNFα release in PCOS. There was a direct relationship between the change in TNFα release from MNC under hyperglycemic culture conditions and abdominal adiposity. It is possible that the inflamed adipose tissue in the abdominal region of obese women with PCOS perpetuates the increased sensitivity of MNC to hyperglycemia manifested by the increased TNFα release observed in culture. Our data also demonstrate a direct relationship between the degree of insulin resistance by ISHOMA and abdominal adiposity. These findings are consistent with previous observations in young adults demonstrating that changes in insulin sensitivity are a function of abdominal adiposity (Kriktetos et al. 2004, Linne 2004). Thus, increased TNFα release from MNC may promote the insulin resistance observed in obese women with PCOS.

The MNC of obese controls and lean women with PCOS exhibited only modest increases in TNFα release in response to hyperglycemia. Both of these groups are in a proinflammatory state, as evidenced by the elevated CRP concentrations in accordance with previous observations (Kelly et al. 1996, Boulman et al. 2004). The lack of statistical significance in the increases in TNFα release in either of these groups and the elevated CRP concentrations in lean women with PCOS may be due to the small sample size. Nevertheless, there is a stepwise increasing trend in the TNFα response, with progressively higher hyperglycemic conditions when study subjects are grouped by body weight. It is possible that the increased abdominal adiposity observed in lean women with PCOS also perpetuates increases in hyperglycemia-induced TNFα release from MNC to promote insulin resistance in this group. Nevertheless, the presence of PCOS in combination with a greater amount of adiposity may explain the higher TNFα response and greater degree of insulin resistance evident in obese women with PCOS.

In PCOS, TNFα release from MNC in response to hyperglycemia may be capable of directly stimulating hyperandrogenism. This is suggested by the direct correlation of the TNFα response with plasma levels of testosterone and androstenedione in women with PCOS. We have also demonstrated direct correlations of ROS generation (González et al. 2006) and activated NFκB (unpublished data) with these androgen levels. Infiltration of the ovary by MNC-derived macrophages has been previously reported (Best et al. 1996). Ovarian steroidogenic enzymes responsible for androgen production are stimulated by oxidative stress and inhibited by antioxidants, such as statins, in vitro (Piotrowski et al. 2005, Rzepczynska et al. 2005). Circulating androgen levels decline in women with PCOS in response to statin therapy in vivo (Banaszewska et al. 2005). TNFα stimulates in vitro proliferation of androgen-producing theca cells (Spazynsky et al. 1999). Thus, it is attractive to consider that increased TNFα release from glucose-activated MNC recruited into the polycystic ovary may be the result of a local inflammatory response that stimulates ovarian androgen production in women with PCOS.

In conclusion, MNC of obese women with PCOS exhibit increased TNFα response when directly exposed to hyperglycemic conditions in vitro in the physiologic range. Our findings suggest that the increased abdominal adiposity in women with PCOS promotes a proinflammatory state, especially in those who are obese. The associations of the TNFα response with measures of adiposity and androgen levels suggest that MNC-derived TNFα release contributes to insulin resistance and hyper-androgenism, particularly when the combination of PCOS and increased adiposity is present.

Table 1

Subject characteristics

ControlPCOS
Lean (n = 6)Obese (n = 6)Lean (n = 6)Obese (n = 6)
Values are expressed as means ± s.e.aObese controls vs lean controls, P < 0.0003; bObese controls vs lean PCOS, P < 0.002; cObese PCOS vs lean controls, P < 0.002; dObese PCOS vs lean PCOS, P < 0.01; eLean PCOS vs lean controls, P < 0.02.
Age (years)33 ± 230 ± 326 ± 228 ± 2
Height (cm)165.6 ± 1.0163.1 ± 3.6165.4 ± 3.9165.7 ± 2.4
Body weight (kg)59.1 ± 2.291.9 ± 4.7a,b63.9 ± 3.596.8 ± 6.0c,d
Body-mass index (kg/m2)21.6 ± 0.834.5 ± 1.2a23.3 ± 0.535.2 ± 1.6c,d
Total body fat (%)27.1 ± 1.843.8 ± 0.4a,b30.7 ± 1.744.2 ± 1.0c,d
Truncal fat (%)22.8 ± 2.443.2 ± 0.6a,b29.7 ± 2.6e45.2 ± 0.9c,d
Waist circumference (cm)71.3 ± 2.0101.1 ± 3.4a,b78.0 ± 2.796.2 ± 8.0c,d
Table 2

Plasma hormone, glucose, insulin and C-reactive protein (CRP) levels

ControlPCOS
Lean (n = 6)Obese (n = 6)Lean (n = 6)Obese (n = 6)
Values are expressed as means ± s.e.aLean PCOS vs lean controls, P < 0.005; bLean PCOS vs obese controls, P < 0.003; cLean PCOS vs obese PCOS, P < 0.05; dObese PCOS vs obese controls, P < 0.02; eObese PCOS vs lean controls, P < 0.05; fObese controls vs lean controls, P < 0.0005.
LH (mlU/ml)3.3 ± 0.42.6 ± 0.314.4 ± 1.7a,b,c7.6 ± 1.2
Testosterone (ng/dl)42.8 ± 5.832.7 ± 6.272.2 ± 6.7a,b67.7 ± 7.4d,e
Androstendione (ng/ml)1.8 ± 0.22.0 ± 0.1b3.2 ± 0.4a,b2.9 ± 0.3d,e
DHEA-S (μg/dl)167 ± 20205 ± 29319 ± 76322 ± 67
Fasting glucose (mg/dl)85.3 ± 2.084.3 ± 3.283.3 ± 3.287.8 ± 1.9
2-h glucose (mg/dl)99.0 ± 11.8121.8 ± 6.0112.5 ± 11.2113.5 ± 16.4
Insulin (μIU/ml)8.5 ± 1.213.7 ± 2.511.5 ± 2.118.6 ± 3.5
CRP (ng/ml)219 ± 926935 ± 139f1314 ± 412b,c6988 ± 1711e
ISHOMA32.1 ± 4.552.8 ± 10.743.1 ± 8.6e73.7 ± 14.8e
Table 3

TNFα release from mononuclear cells (MNC) under euglycemic and hyperglycemic conditions in vitro

5 mM10 mMΔ15 mMΔ
Values are expressed as means ± s.e. Δ: calculated differences between TNFα concentrations under either hyperglycemic condition (10 or 15 mM) and euglycemic baseline (5 mM).
aObese PCOS vs lean controls, P < 0.005; bObese PCOS vs obese controls, P < 0.05.
MNC TNFα (pg/ml)
Lean controls (n = 6)9.4 ± 4.13.6 ± 0.8−5.8 ± 4.06.4 ± 1.8−3.0 ± 2.7
Obese controls (n = 6)4.5 ± 1.44.5 ± 1.50.02 ± 1.68.5 ± 5.38.5 ± 5.3
Lean PCOS (n = 6)3.0 ± 0.45.4 ± 1.82.4 ± 1.67.9 ± 4.54.9 ± 4.5
Obese PCOS (n = 6)3.0 ± 0.714.5 ± 6.111.6 ± 6.0a,b21.9 ± 13.619.0 ± 13.3
Table 4

Spearman rank correlation analysis examining the relationship between the percent change in TNFα release from mononuclear cells and BMI, percent total body fat, percent truncal fat, ISHOMA, testosterone and androstenedione

BMI (kg/m2)Total body fat (%)Truncal fat (%)ISHOMATestosterone (ng/dl)Androstenedione (ng/ml)
The percent change in TNFα release was determined by comparing the (A) 10 mM or (B) 15 mM hyperglycemic condition with the 5 mM euglycemic condition. *P < 0.05.
(A) 10 mM glucose concentration
Combined groups (n = 24)ρ0.4250.3790.4480.3970.2710.645
P0.041*0.0690.032*0.049*0.1930.002*
PCOS (n = 12)ρ0.6010.4550.5100.3920.1820.587
P0.0460.1320.0900.1940.5470.048*
Controls (n = 12)ρ0.3150.4410.4270.336−0.7550.098
P0.2970.1440.1570.2660.012*0.745
(B) 15 mM glucose concentration
Combined groups (n = 24)ρ0.3370.3260.3460.2570.2900.525
P0.107*0.1180.097*0.217*0.1640.012*
PCOS (n = 12)ρ0.3220.1260.1400.1750.5940.245
P0.286*0.6760.6430.5620.048*0.417
Controls (n = 12)ρ0.3570.4970.4480.364−0.6010.427
P0.2370.1000.1380.2280.046*0.157
Figure 1
Figure 1

Percent change in TNFα release from MNC under hyperglycemic conditions (10 and 15 mM) compared with the eugylcemic condition (5 mM, 100% baseline). : lean controls; : obese controls; : lean women with PCOS; : obese women with PCOS. *TNFα response from MNC exposed to 10 mM glucose was significantly higher in obese women with PCOS than in either control group (P < 0.003). †TNFα response from MNC exposed to 15 mM glucose was significantly higher in obese women with PCOS than in either control group (P < 0.04).

Citation: Journal of Endocrinology 188, 3; 10.1677/joe.1.06579

We thank the nursing staff of the General Clinical Research Center for supporting the implementation of the study and assisting with data collection.

Funding
 This research was supported by National Institutes of Health Grants HD-01273 (Women’s Reproductive Health Research Program) to the Department of Obstetrics and Gynecology at MetroHealth Medical Center and MO1 RR-000080 to the General Clinical Research Center. The authors declare that there is no conflict of interest that would prejudice the impartiality of this scientific work.

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  • Corbould A, Kim YB, Youngren JF, Pender C, Kahn BB, Lee A & Dunaif A 2005 Insulin resistance in the skeletal muscle of women with PCOS involves intrinsic and acquired defects in insulin signaling. American Journal of Physiology. Endocrinology and Metabolism 288 E1047–E1054.

    • Search Google Scholar
    • Export Citation
  • Dandona P, Weinstock R, Thusu K, Abdel-Rahman E, Aljada A & Wadden T 1998 Tumor necrosis factor-α in sera of obese patients: fall with weight loss. Journal of Clinical Endocrinology and Metabolism 83 2907–2910.

    • Search Google Scholar
    • Export Citation
  • Dandona P, Mohanty P, Ghanim H, Aljada A, Browne R, Hamouda W, Prabhala A, Afzal A & Garg R 2001a The suppressive effect of dietary restriction and weight loss in the obese on the generation of reactive oxygen species by leukocytes, lipid peroxidation, and protein carbonylation. Journal of Clinical Endocrinology and Metabolism 86 355–362.

    • Search Google Scholar
    • Export Citation
  • Dandona P, Mohanty P, Hamouda W, Ghanim H, Aljada A, Garg R & Kumar V 2001b Inhibitory effect of a two day fast on reactive oxygen species (ROS) generation by leucocytes and plasma orthotyrosine and meta-tyrosine concentrations. Journal of Clinical Endocrinology and Metabolism 86 2899–2902.

    • Search Google Scholar
    • Export Citation
  • Del Aguila LF, Claffey KP & Kirwan JP 1999 TNF-α impairs insulin signaling and insulin stimulation of glucose uptake in C2C12 muscle cells. American Journal of Physiology. Endocrinology and Metabolism 276 E849–E855.

    • Search Google Scholar
    • Export Citation
  • Dunaif A 1999 Insulin resistance and the polycystic ovary syndrome: mechanism and implications for pathogenesis. Endocrine Reviews 18 774–800.

    • Search Google Scholar
    • Export Citation
  • Dunaif A, Wu X, Lee A & Diamanti-Kandarakis E 2001 Defects in insulin receptor signaling in vivo in the polycystic ovary syndrome (PCOS). American Journal of Physiology. Endocrinology and Metabolism 281 E392–E399.

    • Search Google Scholar
    • Export Citation
  • Evans JL, Goldfine ID, Maddux BA & Grodsky GM 2002 Oxidative stress and stress-activated signaling pathways: a unifying hypothesis of type 2 diabetes. Endocrine Reviews 23 599–622.

    • Search Google Scholar
    • Export Citation
  • Fain JN, Bahouth SW & Madan AK 2004a TNFα release by nonfat cells of adipose tissue. International Journal of Obesity 28 616–622.

  • Fain JN, Madan AK, Hyler ML, Cheema P & Bahouth SM 2004b Comparison of the release of adiponectin by adipose tissue, adipose tissue matrix, and adipocytes from visceral and subcutaneous abdominal adipose tissues of obese humans. Endocrinology 145 2273–2282.

    • Search Google Scholar
    • Export Citation
  • Feinstein R, Kanety H, Papa MZ, Lunenfeld B & Karasik A 1993 Tumor necrosis factor α suppresses insulin-induced tyrosine phosphorylation of insulin receptor and its substrates. Journal of Biological Chemistry 268 26055–26058.

    • Search Google Scholar
    • Export Citation
  • González F, Thusu K, Rahman EH, Tomani M & Dandona P 1999 Elevated serum levels of tumor necrosis factor α in normal-weight women with polycystic ovary syndrome. Metabolism 48 437–441.

    • Search Google Scholar
    • Export Citation
  • González F, Rote NS, Minium J & Kirwan JP 2006 Reactive oxygen species-induced oxidative stress in the development of insulin resistance and hyperandrogenism in polycystic ovary syndrome. Journal of Clinical Endocrinology and Metabolism 91 336–340.

    • Search Google Scholar
    • Export Citation
  • Goodarzi MO & Korenman SG 2002 The importance of insulin resistance in polycystic ovary syndrome. Fertility and Sterility 77 255–258.

  • Hotamisligal GS, Shargill NS & Spiegelman BM 1993 Adipose expression of tumor necrosis factor α: direct role in obesity linked insulin resistance. Science 259 87–91.

    • Search Google Scholar
    • Export Citation
  • Hotamisligil GS, Murray DL, Choy LN & Spiegelman BM 1994 Tumor necrosis factor α inhibits signaling from the insulin receptor. PNAS 1 4854–4858.

    • Search Google Scholar
    • Export Citation
  • Hotamisligil GS, Arner P, Caro JF, Atkinson RL & Speigelman BM 1995 Increased adipose tissue expression of tumor necrosis factor α in human obesity and insulin resistance. Journal of Clinical Investigation 95 2409–2415.

    • Search Google Scholar
    • Export Citation
  • Kelly CC, Lyall H, Petrie JR, Gould GW, Connell JMC & Sattar N 1996 Low grade chronic inflammation in women with polycystic ovary syndrome. Journal of Clinical Endocrinology and Metabolism 86 2453–2455.

    • Search Google Scholar
    • Export Citation
  • Knochenhauer ES, Key TJ, Kahser-Miller M, Waggoner W, Boots LR & Azziz R 1998 Prevalence of the polycystic ovary syndrome in unselected black and white women of the southeastern United States: a prospective study. Journal of Clinical Endocrinology and Metabolism 83 3078–3082.

    • Search Google Scholar
    • Export Citation
  • Kohrt WM, Kirwan JP, King DS, Staten MA & Holloszy JO 1993 Insulin resistance of aging is related to abdominal obesity. Diabetes 42 273–281.

    • Search Google Scholar
    • Export Citation
  • Kolterman OG, Insel J, Saekow M & Olefsky JM 1980 Mechanisms of insulin resistance in human obesity. Evidence for receptor and post receptor defects. Journal of Clinical Investigation 65 1272–1284.

    • Search Google Scholar
    • Export Citation
  • Kriktetos AD, Greenfield JR, Peake PW, Furler SM, Denyer GS, Charlesworth JA & Campbell LV 2004 Inflammation, insulin resistance, and adiposity. Diabetes Care 27 2033–2040.

    • Search Google Scholar
    • Export Citation
  • Li M, Youngren JF, Dunaif A, Goldfine ID, Maddux BA, Zhang BB & Evans JL 2002 Decreased insulin receptor (IR) autophosphorylation in fibroblasts from patients with PCOS: effects of serine phosphorylation inhibitors and IR activators. Journal of Clinical Endocrinology and Metabolism 87 4088–4093.

    • Search Google Scholar
    • Export Citation
  • Linne Y 2004 Effects of obesity on women’s reproduction and complications during pregnancy. Obesity Reviews 5 137–143.

  • Matthews DR, Hosker JP, Rudenski AS, Naylor BA, Treacher DF & Turner RC 1985 Homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma glucose and insulin concentrations in man. Diabetologia 28 412–419.

    • Search Google Scholar
    • Export Citation
  • Modan M, Harris MI & Halkin H 1989 Evaluation of WHO and NDDG criteria for impaired glucose tolerance. Results from two national samples. Diabetes 38 1630–1635.

    • Search Google Scholar
    • Export Citation
  • Mohanty P, Hamouda W, Garg R, Aljada A, Ghanim H & Dandona P 2000 Glucose challenge stimulates reactive oxygen species generation by leucocytes. Journal of Clinical Endocrinology and Metabolism 85 2970–2973.

    • Search Google Scholar
    • Export Citation
  • Mohanty P, Ghanim H, Hamouda W, Aljada A, Garg R & Dandona P 2002 Both lipid and protein intakes stimulate increased generation of reactive oxygen species by polymorphonuclear leukocytes and mononuclear cells. American Journal of Clinical Nutrition 75 767–772.

    • Search Google Scholar
    • Export Citation
  • Morohoshi M, Fujisawa K, Uchimura I & Numano F 1996 Glucose-dependent interleukin 6 and tumor necrosis factor production by human peripheral blood monocytes in vitro. Diabetes 45 954–959.

    • Search Google Scholar
    • Export Citation
  • Nestler JE, Jakubowicz DJ, de Vargas AF, Brik C, Quintero N & Medina F 1998 Insulin stimulates testosterone biosynthesis by human theca cells from women with polycystic ovary syndrome by activating its own receptor and using inositoglycan mediators as the signal transduction system. Journal of Clinical Endocrinology and Metabolism 83 2001–2005.

    • Search Google Scholar
    • Export Citation
  • Piotrowski PC, Rzepczynska IJ, Kwintkiewicz J & Duleba AJ 2005 Oxidative stress induces expression of CYP11A, CYP17, STAR and 3βHSD in rat theca-interstitial cells. Journal of the Society for Gynecologic Investigation 12 (Suppl 2) 319A (Abstract).

    • Search Google Scholar
    • Export Citation
  • Rosenbaum D, Haber RS & Dunaif A 1993 Insulin resistance in polycystic ovary syndrome: decreased expression of GLUT 4 glucose transporters in adipocytes. American Journal of Physiology 264 E197–E202.

    • Search Google Scholar
    • Export Citation
  • Rossetti L, Giaccari A & DeFronzo RA 1990 Glucose toxicity. Diabetes Care 13 610–630.

  • Rotterdam ESHRE/ASRM-Sponsored PCOS Conference Workshop Group 2004a Revised 2003 consensus on diagnostic criteria and long-term health risks related to polycystic ovary syndrome. Fertility and Sterility 81 19–25.

    • Search Google Scholar
    • Export Citation
  • Rotterdam ESHRE/ASRM-Sponsored PCOS Conference Workshop Group 2004b Revised 2003 consensus on diagnostic criteria and long-term health risks related to polycystic ovary syndrome. Human Reproduction 19 41–47.

    • Search Google Scholar
    • Export Citation
  • Rui L, Aguirre V, Kim JK, Shulman GI, Lee A, Corbould A, Dunaif A & White MF 2001 Insulin/IGF-1 and TNF-α stimulate phosphorylation of IRS-1 at inhibitory Ser307 via distinct pathways. Journal of Clinical Investigation 107 181–189.

    • Search Google Scholar
    • Export Citation
  • Rzepczynska IJ, Piotrowski PC, Kwintkiewicz J & Duleba AJ 2005 Effect of mevastatin on expression of CYP17, 3βHSD, CYP11A and STAR in rat theca-interstitial cells. Journal of the Society for Gynecologic Investigation 12 (Suppl 2) 320A (Abstract).

    • Search Google Scholar
    • Export Citation
  • Spazynsky RZ, Arici A & Duleba AJ 1999 Tumor necrosis factor alpha stimulates proliferation of rat ovarian theca-interstitial cells. Biology of Reproduction 61 993–998.

    • Search Google Scholar
    • Export Citation
  • Stephens JM & Pekala PH 1991 Transcriptional repression of the GLUT 4 and C/EBP genes in 3T3-L1 adipocytes by tumor necrosis factor α. Journal of Biological Chemistry 266 21839–21845.

    • Search Google Scholar
    • Export Citation
  • Taylor RW, Keil D, Gold EJ, Williams SM & Goulding A 1998 Body mass index, waist girth, and waist to hip ratio as indexes of total and regional adiposity in women: evaluation using receiver operating characteristic curves. American Journal of Clinical Nutrition 67 44–49.

    • Search Google Scholar
    • Export Citation
  • Weisberg SP, McCann D, Desai M, Rosenbaum M, Leibel RL & Ferrante AW Jr 2003 Obesity is associated with macrophage accumulation in adipose tissue. Journal of Clinical Investigation 112 1796–1808.

    • Search Google Scholar
    • Export Citation
  • Wellen KE & Hotamisligil GS 2003 Obesity-induced inflammatory changes in adipose tissue. Journal of Clinical Investigation 112 1785–1788.

    • Search Google Scholar
    • Export Citation
  • Xu H, Barnes GT, Yang Q, Tan G, Yang D, Chou CJ, Sole J, Nichols A, Ross JS, Tartaglia LA et al. 2003 Chronic inflammation in fat plays a crucial role in the development of obesity-related insulin resistance. Journal of Clinical Investigation 112 1821–1830.

    • Search Google Scholar
    • Export Citation
  • Yki-Jarvinen H 1992 Glucose toxicity. Endocrine Reviews 13 415–431.

  • Yudkin JS, Stehouwer CD, Emeis JJ & Coppack SW 1999 C-reactive protein in healthy subjects: associations with obesity, insulin resistance, and endothelial dysfunction: a potential role for cytokines originating from adipose tissue? Arteriosclerosis, Thrombosis, and Vascular Biology 19 972–978.

    • Search Google Scholar
    • Export Citation

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    Percent change in TNFα release from MNC under hyperglycemic conditions (10 and 15 mM) compared with the eugylcemic condition (5 mM, 100% baseline). : lean controls; : obese controls; : lean women with PCOS; : obese women with PCOS. *TNFα response from MNC exposed to 10 mM glucose was significantly higher in obese women with PCOS than in either control group (P < 0.003). †TNFα response from MNC exposed to 15 mM glucose was significantly higher in obese women with PCOS than in either control group (P < 0.04).

  • Aljada A, Mohanty P, Ghanim H, Abdo T, Tripathy D, Chaudari A & Dandona P 2004 Increase in intranuclear nuclear factor kappa B and decrease in inhibitor kappa B in mononuclear cells after a mixed meal: evidence for a proinflammatory effect. American Journal of Clinical Nutrition 79 682–690.

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  • Banaszewska B, Pawelczyk L, Spaczynski RZ, Dziura J & Duleba AJ 2005 Simvastatin improves hyperandrogenism, hyperandrogenemia, LH and lipid profile in women with PCOS: a randomized cross-over study. Fertility and Sterility 84 Suppl 1 S54–S55.

    • Search Google Scholar
    • Export Citation
  • Barnes PJ & Karin M 1997 Nuclear factor-κB: a pivotal transcription factor in chronic inflammatory diseases. New England Journal of Medicine 336 1066–1071.

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    • Export Citation
  • Best CL, Pudney J, Welch WR, Burger N & Hill JA 1996 Localization and characterization of white blood cell populations within the human ovary throughout the menstrual cycle and menopause. Human Reproduction 11 790–797.

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    • Export Citation
  • Boulman N, Leiba LR, Shachar S, Linn R, Zinder O & Blumenfeld Z 2004 Increased c-reactive protein levels in the polycystic ovary syndrome: a marker of cardiovascular disease. Journal of Clinical Endocrinology and Metabolism 89 2160–2165.

    • Search Google Scholar
    • Export Citation
  • Boyam A 1968 Isolation of mononuclear cells and granulocytes from human blood. Scandinavian Journal of Clinical Laboratory Investigation 21 (Suppl 97) 77–89.

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  • Burghen GA, Givens JR & Kitabachi AE 1980 Correlation of hyperandrogenism with hyperinsulinemia in polycystic ovarian disease. Journal of Clinical Endocrinology and Metabolism 50 113–116.

    • Search Google Scholar
    • Export Citation
  • Ciaraldi TP, Kolterman OG & Olefsky JM 1981 Mechanism for the postreceptor defect in insulin action in human obesity. Decrease in glucose transport system activity. Journal of Clinical Investigation 68 875–878.

    • Search Google Scholar
    • Export Citation
  • Corbould A, Kim YB, Youngren JF, Pender C, Kahn BB, Lee A & Dunaif A 2005 Insulin resistance in the skeletal muscle of women with PCOS involves intrinsic and acquired defects in insulin signaling. American Journal of Physiology. Endocrinology and Metabolism 288 E1047–E1054.

    • Search Google Scholar
    • Export Citation
  • Dandona P, Weinstock R, Thusu K, Abdel-Rahman E, Aljada A & Wadden T 1998 Tumor necrosis factor-α in sera of obese patients: fall with weight loss. Journal of Clinical Endocrinology and Metabolism 83 2907–2910.

    • Search Google Scholar
    • Export Citation
  • Dandona P, Mohanty P, Ghanim H, Aljada A, Browne R, Hamouda W, Prabhala A, Afzal A & Garg R 2001a The suppressive effect of dietary restriction and weight loss in the obese on the generation of reactive oxygen species by leukocytes, lipid peroxidation, and protein carbonylation. Journal of Clinical Endocrinology and Metabolism 86 355–362.

    • Search Google Scholar
    • Export Citation
  • Dandona P, Mohanty P, Hamouda W, Ghanim H, Aljada A, Garg R & Kumar V 2001b Inhibitory effect of a two day fast on reactive oxygen species (ROS) generation by leucocytes and plasma orthotyrosine and meta-tyrosine concentrations. Journal of Clinical Endocrinology and Metabolism 86 2899–2902.

    • Search Google Scholar
    • Export Citation
  • Del Aguila LF, Claffey KP & Kirwan JP 1999 TNF-α impairs insulin signaling and insulin stimulation of glucose uptake in C2C12 muscle cells. American Journal of Physiology. Endocrinology and Metabolism 276 E849–E855.

    • Search Google Scholar
    • Export Citation
  • Dunaif A 1999 Insulin resistance and the polycystic ovary syndrome: mechanism and implications for pathogenesis. Endocrine Reviews 18 774–800.

    • Search Google Scholar
    • Export Citation
  • Dunaif A, Wu X, Lee A & Diamanti-Kandarakis E 2001 Defects in insulin receptor signaling in vivo in the polycystic ovary syndrome (PCOS). American Journal of Physiology. Endocrinology and Metabolism 281 E392–E399.

    • Search Google Scholar
    • Export Citation
  • Evans JL, Goldfine ID, Maddux BA & Grodsky GM 2002 Oxidative stress and stress-activated signaling pathways: a unifying hypothesis of type 2 diabetes. Endocrine Reviews 23 599–622.

    • Search Google Scholar
    • Export Citation
  • Fain JN, Bahouth SW & Madan AK 2004a TNFα release by nonfat cells of adipose tissue. International Journal of Obesity 28 616–622.

  • Fain JN, Madan AK, Hyler ML, Cheema P & Bahouth SM 2004b Comparison of the release of adiponectin by adipose tissue, adipose tissue matrix, and adipocytes from visceral and subcutaneous abdominal adipose tissues of obese humans. Endocrinology 145 2273–2282.

    • Search Google Scholar
    • Export Citation
  • Feinstein R, Kanety H, Papa MZ, Lunenfeld B & Karasik A 1993 Tumor necrosis factor α suppresses insulin-induced tyrosine phosphorylation of insulin receptor and its substrates. Journal of Biological Chemistry 268 26055–26058.

    • Search Google Scholar
    • Export Citation
  • González F, Thusu K, Rahman EH, Tomani M & Dandona P 1999 Elevated serum levels of tumor necrosis factor α in normal-weight women with polycystic ovary syndrome. Metabolism 48 437–441.

    • Search Google Scholar
    • Export Citation
  • González F, Rote NS, Minium J & Kirwan JP 2006 Reactive oxygen species-induced oxidative stress in the development of insulin resistance and hyperandrogenism in polycystic ovary syndrome. Journal of Clinical Endocrinology and Metabolism 91 336–340.

    • Search Google Scholar
    • Export Citation
  • Goodarzi MO & Korenman SG 2002 The importance of insulin resistance in polycystic ovary syndrome. Fertility and Sterility 77 255–258.

  • Hotamisligal GS, Shargill NS & Spiegelman BM 1993 Adipose expression of tumor necrosis factor α: direct role in obesity linked insulin resistance. Science 259 87–91.

    • Search Google Scholar
    • Export Citation
  • Hotamisligil GS, Murray DL, Choy LN & Spiegelman BM 1994 Tumor necrosis factor α inhibits signaling from the insulin receptor. PNAS 1 4854–4858.

    • Search Google Scholar
    • Export Citation
  • Hotamisligil GS, Arner P, Caro JF, Atkinson RL & Speigelman BM 1995 Increased adipose tissue expression of tumor necrosis factor α in human obesity and insulin resistance. Journal of Clinical Investigation 95 2409–2415.

    • Search Google Scholar
    • Export Citation
  • Kelly CC, Lyall H, Petrie JR, Gould GW, Connell JMC & Sattar N 1996 Low grade chronic inflammation in women with polycystic ovary syndrome. Journal of Clinical Endocrinology and Metabolism 86 2453–2455.

    • Search Google Scholar
    • Export Citation
  • Knochenhauer ES, Key TJ, Kahser-Miller M, Waggoner W, Boots LR & Azziz R 1998 Prevalence of the polycystic ovary syndrome in unselected black and white women of the southeastern United States: a prospective study. Journal of Clinical Endocrinology and Metabolism 83 3078–3082.

    • Search Google Scholar
    • Export Citation
  • Kohrt WM, Kirwan JP, King DS, Staten MA & Holloszy JO 1993 Insulin resistance of aging is related to abdominal obesity. Diabetes 42 273–281.

    • Search Google Scholar
    • Export Citation
  • Kolterman OG, Insel J, Saekow M & Olefsky JM 1980 Mechanisms of insulin resistance in human obesity. Evidence for receptor and post receptor defects. Journal of Clinical Investigation 65 1272–1284.

    • Search Google Scholar
    • Export Citation
  • Kriktetos AD, Greenfield JR, Peake PW, Furler SM, Denyer GS, Charlesworth JA & Campbell LV 2004 Inflammation, insulin resistance, and adiposity. Diabetes Care 27 2033–2040.

    • Search Google Scholar
    • Export Citation
  • Li M, Youngren JF, Dunaif A, Goldfine ID, Maddux BA, Zhang BB & Evans JL 2002 Decreased insulin receptor (IR) autophosphorylation in fibroblasts from patients with PCOS: effects of serine phosphorylation inhibitors and IR activators. Journal of Clinical Endocrinology and Metabolism 87 4088–4093.

    • Search Google Scholar
    • Export Citation
  • Linne Y 2004 Effects of obesity on women’s reproduction and complications during pregnancy. Obesity Reviews 5 137–143.

  • Matthews DR, Hosker JP, Rudenski AS, Naylor BA, Treacher DF & Turner RC 1985 Homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma glucose and insulin concentrations in man. Diabetologia 28 412–419.

    • Search Google Scholar
    • Export Citation
  • Modan M, Harris MI & Halkin H 1989 Evaluation of WHO and NDDG criteria for impaired glucose tolerance. Results from two national samples. Diabetes 38 1630–1635.

    • Search Google Scholar
    • Export Citation
  • Mohanty P, Hamouda W, Garg R, Aljada A, Ghanim H & Dandona P 2000 Glucose challenge stimulates reactive oxygen species generation by leucocytes. Journal of Clinical Endocrinology and Metabolism 85 2970–2973.

    • Search Google Scholar
    • Export Citation
  • Mohanty P, Ghanim H, Hamouda W, Aljada A, Garg R & Dandona P 2002 Both lipid and protein intakes stimulate increased generation of reactive oxygen species by polymorphonuclear leukocytes and mononuclear cells. American Journal of Clinical Nutrition 75 767–772.

    • Search Google Scholar
    • Export Citation
  • Morohoshi M, Fujisawa K, Uchimura I & Numano F 1996 Glucose-dependent interleukin 6 and tumor necrosis factor production by human peripheral blood monocytes in vitro. Diabetes 45 954–959.

    • Search Google Scholar
    • Export Citation
  • Nestler JE, Jakubowicz DJ, de Vargas AF, Brik C, Quintero N & Medina F 1998 Insulin stimulates testosterone biosynthesis by human theca cells from women with polycystic ovary syndrome by activating its own receptor and using inositoglycan mediators as the signal transduction system. Journal of Clinical Endocrinology and Metabolism 83 2001–2005.

    • Search Google Scholar
    • Export Citation
  • Piotrowski PC, Rzepczynska IJ, Kwintkiewicz J & Duleba AJ 2005 Oxidative stress induces expression of CYP11A, CYP17, STAR and 3βHSD in rat theca-interstitial cells. Journal of the Society for Gynecologic Investigation 12 (Suppl 2) 319A (Abstract).

    • Search Google Scholar
    • Export Citation
  • Rosenbaum D, Haber RS & Dunaif A 1993 Insulin resistance in polycystic ovary syndrome: decreased expression of GLUT 4 glucose transporters in adipocytes. American Journal of Physiology 264 E197–E202.

    • Search Google Scholar
    • Export Citation
  • Rossetti L, Giaccari A & DeFronzo RA 1990 Glucose toxicity. Diabetes Care 13 610–630.

  • Rotterdam ESHRE/ASRM-Sponsored PCOS Conference Workshop Group 2004a Revised 2003 consensus on diagnostic criteria and long-term health risks related to polycystic ovary syndrome. Fertility and Sterility 81 19–25.

    • Search Google Scholar
    • Export Citation
  • Rotterdam ESHRE/ASRM-Sponsored PCOS Conference Workshop Group 2004b Revised 2003 consensus on diagnostic criteria and long-term health risks related to polycystic ovary syndrome. Human Reproduction 19 41–47.

    • Search Google Scholar
    • Export Citation
  • Rui L, Aguirre V, Kim JK, Shulman GI, Lee A, Corbould A, Dunaif A & White MF 2001 Insulin/IGF-1 and TNF-α stimulate phosphorylation of IRS-1 at inhibitory Ser307 via distinct pathways. Journal of Clinical Investigation 107 181–189.

    • Search Google Scholar
    • Export Citation
  • Rzepczynska IJ, Piotrowski PC, Kwintkiewicz J & Duleba AJ 2005 Effect of mevastatin on expression of CYP17, 3βHSD, CYP11A and STAR in rat theca-interstitial cells. Journal of the Society for Gynecologic Investigation 12 (Suppl 2) 320A (Abstract).

    • Search Google Scholar
    • Export Citation
  • Spazynsky RZ, Arici A & Duleba AJ 1999 Tumor necrosis factor alpha stimulates proliferation of rat ovarian theca-interstitial cells. Biology of Reproduction 61 993–998.

    • Search Google Scholar
    • Export Citation
  • Stephens JM & Pekala PH 1991 Transcriptional repression of the GLUT 4 and C/EBP genes in 3T3-L1 adipocytes by tumor necrosis factor α. Journal of Biological Chemistry 266 21839–21845.

    • Search Google Scholar
    • Export Citation
  • Taylor RW, Keil D, Gold EJ, Williams SM & Goulding A 1998 Body mass index, waist girth, and waist to hip ratio as indexes of total and regional adiposity in women: evaluation using receiver operating characteristic curves. American Journal of Clinical Nutrition 67 44–49.

    • Search Google Scholar
    • Export Citation
  • Weisberg SP, McCann D, Desai M, Rosenbaum M, Leibel RL & Ferrante AW Jr 2003 Obesity is associated with macrophage accumulation in adipose tissue. Journal of Clinical Investigation 112 1796–1808.

    • Search Google Scholar
    • Export Citation
  • Wellen KE & Hotamisligil GS 2003 Obesity-induced inflammatory changes in adipose tissue. Journal of Clinical Investigation 112 1785–1788.

    • Search Google Scholar
    • Export Citation
  • Xu H, Barnes GT, Yang Q, Tan G, Yang D, Chou CJ, Sole J, Nichols A, Ross JS, Tartaglia LA et al. 2003 Chronic inflammation in fat plays a crucial role in the development of obesity-related insulin resistance. Journal of Clinical Investigation 112 1821–1830.

    • Search Google Scholar
    • Export Citation
  • Yki-Jarvinen H 1992 Glucose toxicity. Endocrine Reviews 13 415–431.

  • Yudkin JS, Stehouwer CD, Emeis JJ & Coppack SW 1999 C-reactive protein in healthy subjects: associations with obesity, insulin resistance, and endothelial dysfunction: a potential role for cytokines originating from adipose tissue? Arteriosclerosis, Thrombosis, and Vascular Biology 19 972–978.

    • Search Google Scholar
    • Export Citation