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ABSTRACT
Androgenic regulation of one of the esteroproteinases (proteinase F) in the mouse submandibular gland was studied using specific antiserum. In contrast to esteroproteinases such as proteinases A, D or P-esterase, proteinase F content in male but not in female mice was increased by gonadectomy and decreased by the injection of various androgens. In-vivo incorporation of [3H]leucine into proteinase F in males was increased after castration and decreased by the injection of testosterone propionate; androgens inhibited the denovo synthesis of proteinase F in male mice. The dose–response curves for testosterone propionate and time-courses following castration or after the injection of testosterone propionate were reciprocal between proteinase F and total esteroproteinase activity. Proteinase F, like other esteroproteinases in the submandibular gland of the mouse, was localized in granular convoluted tubular cells. These data indicate that granular convoluted tubular cells of the male mouse submandibular gland synthesize both androgen-inducible proteinases and androgen-inhibitory proteinase (proteinase F).
J. Endocr. (1984) 100, 253–262
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ABSTRACT
Evidence is accumulating that adrenal steroids may be involved in the metabolic effects of cytokines. We evaluated the possible involvement of glucocorticoids in the inhibition of pancreatic insulin secretion by interleukin-1β (IL-1β), one of the cytokines produced by inflammatory cells. In the first group of experiments, adrenalectomized rats showed a significant reduction in basal and glucose (0·5 g/kg, i.v.)-stimulated immunoreactive insulin (IRI) levels after injection of IL-1β (1·0 μg/kg), but intact rats did not. Pretreatment with IL-1β increased plasma glucose levels 2 and 15 min after an i.v. bolus of glucose in adrenalectomized rats. In the second group of experiments, dexamethasone supplement (0·1 mg/kg) given to adrenalectomized rats cancelled the reduction in plasma glucose levels by IL-1β, and rats treated with 1·0 mg dexamethasone/kg showed a significant increase in basal IRI levels and enhanced serum IRI levels after IL-1β injection. However, 1·0 mg deoxycorticosterone/kg given daily for 7 days failed to cancel the effect of IL-1β on the reduction of serum IRI levels, although it attenuated the weight loss after adrenalectomy. The data suggested that withdrawal of glucocorticoids after adrenalectomy potentiates the effect of IL-1β on the reduction of serum IRI levels. Glucocorticoids may have a protective action against the reduction of serum IRI levels by IL-1β.
Journal of Endocrinology (1992) 132, 419–423
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Ghrelin was recently isolated from the rat stomach as an endogenous ligand for the GH secretagogue receptor. Although it is well known that a large amount of ghrelin is produced in the gastrointestinal tract, developmental changes in ghrelin mRNA expression and differentiation of ghrelin-immunopositive (ghrelin-ip) and mRNA-expressing (ghrelin-ex) cells in the stomach have not been elucidated. In this study, we therefore investigated the changes in ghrelin mRNA expression levels and in the numbers of ghrelin-ip and -ex cells in the stomachs of 1- to 8-week-old male and female rats by Northern blot analysis, immunohistochemistry and in situ hybridization. Northern blot analysis showed that the level of weak ghrelin mRNA expression was low in the postnatal period but then increased in a dimorphic pattern, i.e. transient stagnation at 4 weeks in the male rats and at 5 weeks in the female rats. The number of ghrelin-ip and ghrelin-ex cells also increased after birth, and more numerous ghrelin cells were found in female rats than in male rats, and this finding was confirmed by Northern blot analysis. Ghrelin-ip and -ex cells first appeared in the glandular base of the fundic gland and then they were found in the glandular base and the glandular neck at 3 weeks of age, suggesting that the distribution of ghrelin cells is extended from the glandular base to the glandular neck during the postneonatal development period. This is the first report on detailed changes in postneonatal ghrelin expression level and in the number of ghrelin cells in the rat stomach. The sexual dimorphism of ghrelin expression and ghrelin cell differentiation suggest that ghrelin plays an important physiological role in the stomach.
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ABSTRACT
Advances in techniques in molecular biology have facilitated the research into endogenous opioids and related peptides in several ways. The organization and expression of genes and the primary structure of three precursor proteins of opioid peptides have been elucidated. These studies predicted the presence of potentially bioactive peptides, which has been confirmed by later studies. Advances in techniques in protein chemistry have helped to elucidate the distribution and molecular forms of endogenous opioids and related peptides in the body, and the processing of precursor proteins. Studies on the function of these peptides have shown a broad spectrum of actions. Leumorphin, a newly identified peptide, has been shown to exhibit unique biological activities. In spite of extensive studies, the physiological and pathophysiological significance of opioid peptide systems are not yet completely understood. This is mainly due to the paucity of our knowledge about opioid receptors. Further studies on the subtypes of opioid receptors will help to elucidate all aspects of the function of endogenous opioids and related peptides.
J. Endocr. (1985) 107, 147–157
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We previously reported that transgenic (Tg) expression of adiponectin significantly prolonged the lifespan of normal mice. The aim of this study was to elucidate the mechanism involved in the longevity effects of adiponectin using KK/Ta mice, a murine model of metabolic syndrome. We established a Tg line of KK/Ta (Tg-KK/Ta) mice expressing human adiponectin in the liver, and assessed their lifespan. The cause of death was determined by macroscopic and microscopic examinations immediately after death. The expressions of SIRT1, C-reactive protein (CRP), inflammatory cytokines, AMPK, and AKT were measured by quantitative real-time PCR, ELISAs, and/or western blotting. KK/Ta mice had lower serum adiponectin levels and shorter lifespan (57.6±13.9 vs 106.5±18.3 weeks, P<0.0001) than C57BL/6N mice. Tg adiponectin expression significantly extended the lifespan of KK/Ta mice (73.6±16.6 weeks, P<0.001) without affecting body weight, daily food consumption, or plasma glucose levels. Neoplasms were observed in only three of 22 KK/Ta mice that died spontaneously because of tumors. Atherosclerotic lesions were not detected in any mice. SIRT1 levels were not significantly different between KK/Ta and Tg-KK/Ta mice. Gene expressions of Crp, Tnf α, Il6, and Nf κ b were increased in KK/Ta mice, but they were significantly attenuated in Tg-KK/Ta mice. Phosphorylated AMPK levels were increased and phosphorylated AKT levels were decreased in Tg-KK/Ta mice. The anti-inflammatory effects of adiponectin, achieved by inhibiting the AKT signaling pathway, may explain how adiponectin slows the accelerated aging process associated with the metabolic syndrome.
