Search Results

You are looking at 1 - 6 of 6 items for

  • Author: S Maier x
Clear All Modify Search
Restricted access

F. SAKAI, F. CHEIX, M. CLAVEL, J. COLON, M. MAYER, E. POMMATAU and S. SAEZ

The effects of tamoxifen on cortisol binding globulin (CBG) and sex hormone binding globulin (SHBG) were studied in 25 women and one man with breast cancer. These patients were in various endocrine states according to age (15 post-menopausal women) or previous endocrine surgery (ovariectomy, two patients; ovariectomy plus adrenal surgery, five patients; hypophysectomy, three patients; ovariectomy plus hypophysectomy, two patients). The administration of tamoxifen (20–40 mg/day) resulted in increases in the level of CBG in all patients (mean rise in binding capacity 10·8 μg cortisol/100 ml plasma) and in the level of SHBG in 21 patients (mean rise in binding capacity 0·79 μg dihydrotestosterone/ 100 ml plasma for all patients). These increases were positively correlated. They were not associated with any alteration in the association constants of the steroid binding globulins. The effect of tamoxifen on CBG diminished with increasing age. The changes in the levels of CBG and SHBG were independent of the endocrinological state of the patient. It is inferred that tamoxifen has a direct oestrogen-like action on the liver which results in increased production of CBG and SHBG. Tamoxifen therapy for carcinoma of the breast appeared to be least effective in those patients in whom the drug caused the highest increase in the concentration of CBG.

Restricted access

J S Mayes, J P McCann, T C Ownbey and G H Watson

Abstract

Differing risk factors between men and women for a number of vascular and metabolic diseases have been linked to regional obesity. The differences in the distribution of adipose tissues between men (abdominal or upper-body obesity) and women (gluteal/femoral or lower body obesity) suggest a role for sex steroids in the regional distribution of fat. Previous work from this laboratory has shown the presence of oestrogen receptor (ER) in gluteal, perirenal and omental adipose tissues of ewes with similar physical characteristics to the ER in uterine tissue. The concentration profile for adipose ER was gluteal> perirenal>omental. In this report, we determined the physiological significance of adipose ERs by showing an up-regulation of the progesterone receptor (PR) in adipose tissues after oestrogen treatment in a fashion similar to that seen in a major responsive tissue such as uterus. Using PR antibodies (PR-6 and C-262), Western blot analysis of PR from oestrogen-treated sheep indicated that PR was induced in uterus>>>gluteal adipose>perirenal adipose consistent with the concentration of ER contained in these tissues. PR could not be detected by Western blotting in omental adipose tissue from oestrogen-treated animals or in gluteal, perirenal and omental adipose tissues from untreated animals. Sucrose gradient profiles of progestin (R-5020) binding from uterus and gluteal adipose tissues of oestrogen-treated ewes showed specific binding in both the 5S and 9S regions of the gradient, while perirenal and omental adipose tissue had only the 5S peak. The amount of specific binding was increased with oestrogen treatment in all the tissues. When gluteal adipose tissue cytosol was preincubated with PR antibody (C-262) to prevent binding of ligand and subjected to sucrose gradient analysis, both the 5S and 9S regions were diminished, suggesting that both peaks contained PR. Dilution of uterine cytosol resulted in an increase in the ratio of the 5S to the 9S peak, indicating that the 9S PR complex dissociates at low concentrations; this may be the reason why only the 5S peak was observed in perirenal and omental adipose tissues. These data offer further support for a direct role of sex steroids in regional adipose accretion and metabolism.

Journal of Endocrinology (1996) 148, 19–25

Restricted access

G. H. Watson, J. L. Manes, J. S. Mayes and J. P. McCann

ABSTRACT

Determination of the presence and characterization of oestrogen receptors (ERs) in subcutaneous and internal fat depots were performed and compared with ERs in the uterus using ligand binding and immunological techniques. Successful and consistent measurement of ERs in ovine adipose tissue could only be accomplished in animals depleted of endogenous sex steroids by combined ovariectomy and adrenalectomy. Scatchard, sucrose gradient and Western blot analyses all confirmed the presence of ERs in the cytosolic fractions of various adipose and uterine tissues from ovariectomized-adrenalectomized ewes. The approximate K d values of 0·1–0·4 nmol/l for oestradiol binding in cytosolic fractions of gluteal, omental and perirenal adipose tissues were similar to the expected high affinity binding of K d 0·35 nmol/l observed in uterine tissue. The binding was specific for oestrogens, as unlabelled diethylstilboestrol and oestradiol effectively competed with labelled hormone for receptor sites and progesterone, R5020, testosterone and dexamethasone all failed to compete. Mean (± s.e.m.) concentrations of ERs, expressed as fmol specific binding sites per mg protein, were much lower (P<0·05) in adipose tissues than in uterine tissue (975 ± 33). However, the content of ERs was greater (P<0·05) in subcutaneous gluteal fat (11·5 ± 0·8) than in the internal omental or perirenal fat (5 ± 0·6) depots. ERs from adipose and uterine tissues both migrated as moieties of 8S on 5–20% sucrose gradients. Western blot analysis of ERs from uterine and adipose tissues in the presence of protease inhibitors demonstrated an immunostaining band with a molecular mass of 67 kDa. In the absence of protease inhibitors, the adipose ER was degraded into two smaller bands with molecular masses of 45 kDa and 36 kDa.

In conclusion, these results support the presence of specific ERs in adipose tissues of sheep with characteristics similar to those of the ERs of the uterus. Furthermore, their presence is supportive of sex steroid-dependent effects on adipose accretion and metabolism.

Journal of Endocrinology (1993) 139, 107–115

Free access

W Karges, K Jostarndt, S Maier, A Flemming, M Weitz, A Wissmann, B Feldmann, H Dralle, P Wagner and BO Boehm

Germ line mutations of the multiple endocrine neoplasia type 1 (MEN1) tumour suppressor gene cause MEN1, a rare familial tumour syndrome associated with parathyroid hyperplasia, adenoma and hyperparathyroidism (HP). Here we investigated the role of the MEN1 gene in isolated sporadic and familial HP. Using RT-PCR single-strand conformational polymorphism screening, somatic (but not germ line) mutations of the MEN1 coding sequence were identified in 6 of 31 (19.3%) adenomas from patients with sporadic primary HP, but none in patients (n=16) with secondary HP due to chronic renal failure. MEN1 mutations were accompanied by a loss of heterozygosity (LOH) for the MEN1 locus on chromosome 11q13 in the adenomas as detected by microsatellite analysis. No DNA sequence divergence within the 5' region of the MEN1 gene, containing the putative MEN1 promoter, was detectable in HP adenomas. Clinical characteristics were not different in HP patients with or without MEN1 mutation. Heterozygous MEN1 gene polymorphisms were identified in 9.6% and 25% of patients with primary and secondary HP respectively. In a large kindred with familial isolated familial HP, MEN1 germ line mutation 249 del4 and LOH was associated with the HP phenotype and a predisposition to non-endocrine malignancies. We suggest that the bi-allelic somatic loss of MEN1 wild-type gene expression is involved in the pathogenesis of a clinically yet undefined subset of sporadic primary HP adenomas. MEN1 genotyping may further help define the familial hyperparathyroidism-MEN1 disease complex, but it seems dispensable in sporadic primary HP.

Free access

Nancy H Nabilsi, Russell R Broaddus, Adrienne S McCampbell, Karen H Lu, Henry T Lynch, Lee-may Chen and David S Loose

Survivin (BIRC5) is a cell survival gene that is overexpressed in endometrial cancer and has been implicated to have a physiological role in normal endometrial function. To determine whether survivin gene expression is regulated by reproductive steroid hormones in the human endometrium, RNA was prepared from normal cycling women in the proliferative and secretory phases of the menstrual cycle. RNA was also isolated from 21 endometrial biopsies from premenopausal women at baseline and following 3 months of treatment with depot medroxyprogesterone acetate. Finally, RNA was isolated from endometrial biopsies from ten healthy postmenopausal women participating in a clinical trial of estrogen replacement therapy at baseline and following 6 months of treatment with conjugated equine estrogen. Quantitative RT-PCR analysis was used to determine survivin, insulin-like growth factor binding protein 1 (IGFBP1), Ki67, and IGF1 gene expression levels. Survivin gene expression was highest in the proliferative phase of the menstrual cycle and showed a statistically significant 4-fold increase in expression following chronic treatment with estrogens; this was strongly correlated with increased Ki67, a marker of proliferation. Survivin gene expression decreased 4.6-fold following chronic progestin treatment in the human endometrium. These data suggest that survivin transcript is regulated by estrogens and progestins in the disease-free human endometrium. The data also suggest that survivin transcript may be used as a biomarker of estrogen and progestin treatment efficacy, but validation studies must be conducted to support this conclusion.

Free access

D S Gardner, B W M Van Bon, J Dandrea, P J Goddard, S F May, V Wilson, T Stephenson and M E Symonds

Glucocorticoids are proposed to act as intermediary factors that transcribe the developmental programming sequelae of maternal nutrient restriction (NR). Periconceptional under-nutrition of sheep markedly activates fetal hypothalamic–pituitary–adrenal (HPA) axis activity leading to preterm birth, while transient undernutrition during late gestation in sheep programs adult HPA axis function. To date, no study has examined resting or stimulated HPA axis function in young adult offspring following a periconceptional nutritional challenge. In the present study, 20 ewes were either periconceptionally undernourished (50% metabolisable energy requirements from days 1 to 30 gestation; NR, n = 8) or fed to control levels (100% requirement; controls, n = 12) to term (147 days gestation). Ewes were blood sampled remotely at 2 and 30 days using automated blood sampling equipment. Thereafter, offspring (controls, n = 6/6 males/females; NR, n = 4/4 males/females) were reared to 1 year of age and on separate days received either an i.v. corticotrophin-releasing hormone (CRH; 0.5 μg/kg) and vasopressin (AVP; 0.1 μg/kg) challenge or a synthetic ACTH i.v. bolus (Synacthen; 1.25 μg/kg), and blood samples were taken (manually and remotely) at appropriate intervals for measurement of plasma ACTH and cortisol accordingly. Resting plasma cortisol, assessed remotely, was similar in ewes during undernutrition (control 18.3 ± 1.4 vs NR 23.4 ± 1.9 nmol/l) and in offspring at 4 months of age (control male 17.6 ± 2.9; control female 17.2 ± 0.4, NR male 16.5 ± 3.1, NR female 21.7 ± 4.0 nmol/l). At 12 months of age, however, resting plasma cortisol was significantly increased in NR females (control male 28.0 ± 1.5, control female 32.9 ± 9, NR male 32 ± 7, NR female 53 ± 10 nmol/l, F 5.7, P = 0.02) despite no difference in plasma ACTH concentration. There was an interaction between nutritional group and gender for both the pituitary and adrenal responses to CRH and AVP, i.e. for controls, females exhibited increased plasma ACTH or cortisol relative to males but for NR this trend was either not present or reversed. The adrenocortical response to synthetic ACTH was gender-dependent only, being greater in female offspring. Combined CRH and AVP provoked a transient hypertension and marked bradycardia in all animals, irrespective of dietary group or gender and could be effectively reproduced by an AVP bolus alone. In conclusion, the present study has shown that periconceptional undernutrition of sheep has only a minor influence on HPA axis function in their young adult offspring when considered alongside the effect of gender per se.