Please use this identifier to cite or link to this item: http://dl.umsu.ac.ir/handle/10722/146620
Title: Dexamethasone decreases somatostatin mRNA levels in the periventricular nucleus of the rat hypothalamus
Authors: Lam, KSL;Srivastava, G;Chung, LP;Tang, F;Chung, SK;Tam, SP;Chan, SF
subject: Dexamethasone;Gene Expression;Glucocorticoid;Hypothalamus;In situ hybridization;Periventricular nucleus;Somatostatin
Year: 1993
Publisher: S Karger AG. The Journal's web site is located at http://www.karger.com/NEN
Switzerland
Description: Glucocorticoid excess inhibits somatic growth in man and laboratory animals. While the mechanism involved is likely to be multifactorial, indirect evidence suggesting the role of an enhanced endogenous somatostatin (SS) tone has been reported. However, there has been no direct evidence indicating an increased synthesis or secretion of hypothalamic SS. In this study, we investigated the effects of glucocorticoids on hypothalamic SS expression by measuring the peptide and mRNA content of SS in whole hypothalamic blocks of male Sprague-Dawley rats sacrificed 4 weeks after adrenalectomy or sham operation. Adrenalectomy decreased the SS content in the rat hypothalamus (p < 0.05), an effect which was reversed by dexamethasone treatment for 10 days. On the other hand, total hypothalamic SS mRNA levels were unaffected by adrenalectomy, but became significantly decreased following dexamethasone treatment (p < 0.05). Using in situ hybridization, this reduction in SS gene expression was shown to occur consistently in the periventricular nucleus and in the parvocellular subdivision of the paraventricular nucleus. The effects of adrenalectomy and dexamethasone on SS mRNA levels were further quantitated in hypothalamic fragments containing predominantly the periventricular and paraventricular nuclei. Somatostatin mRNA levels in these tissue fragments were marginally increased by adrenalectomy (p < 0.05), but showed a 50% reduction following dexamethasone treatment (p < 0.0001). In conclusion, our findings suggest that the inhibitory effect of glucocorticoids on somatic growth is probably not mediated via an effect on hypothalamic SS gene expression.
URI: http://hub.hku.hk/handle/10722/146620
Standard no: Neuroendocrinology, 1993, v. 58 n. 3, p. 325-331
331
WOS:A1993ME44200008
0028-3835
3
7902961
eid_2-s2.0-0027484952
325
58
Appears in Collections:Department of Anatomy

Files in This Item:
Click on the URI links for accessing contents.


Items in HannanDL are protected by copyright, with all rights reserved, unless otherwise indicated.