Document Detail

Downregulation of melanocortin-4 receptor during refeeding and its modulation by adrenalectomy in rats.
MedLine Citation:
PMID:  18810709     Owner:  NLM     Status:  MEDLINE    
Melanocortin system and corticotropin releasing hormone (CRH) are implicated in the control of feeding behavior. Besides its anorexigenic effect on food intake, CRH is one of the most important regulators of hypothalamic-pituitary-adrenal (HPA) axis activity. Therefore, there could be an interplay between HPA axis activity and melanocortin system. We investigated the expression of melanocortin-4 receptor (MC4-R) mRNA in the hypothalamus of rats after 14 days of food restriction or after a fasting-refeeding regimen, in sham or adrenalectomized rats. Male Wistar rats were subjected to free access to food or food ingestion restricted for 2 h a day (8-10 AM) during 14 d, when plasma corticosterone, ACTH, insulin, leptin concentrations, and MC4-R mRNA expression were determined before and after refeeding. Another set of rats was fasted for 48 h, followed by refeeding during 2 or 4 h on the seventh day after adrenalectomy (ADX) or sham surgery. On the day of the experiment, rats were anesthetized and perfused and the brain processed for MC4-R mRNA by in situ hybridization. Long-term reduction of food intake, either secondary to food restriction or adrenalectomy, reduced body weight gain and also leptin and insulin plasma concentrations. Food ingestion reduced MC4-R expression in the paraventricular nucleus in naive rats subjected to food restriction and also in sham rats fasted for 48 h. However, after ADX, MC4-R expression was not changed by refeeding. In conclusion, the present data indicate that MC4-R expression is downregulated by food ingestion and this response could be modulated by glucocorticoid withdrawal.
C M R Germano; M de Castro; R Rorato; D B Costa; J Antunes-Rodrigues; C F Elias; L L K Elias
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-09-22
Journal Detail:
Title:  Hormone and metabolic research = Hormon- und Stoffwechselforschung = Hormones et métabolisme     Volume:  40     ISSN:  0018-5043     ISO Abbreviation:  Horm. Metab. Res.     Publication Date:  2008 Dec 
Date Detail:
Created Date:  2008-11-14     Completed Date:  2009-03-05     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0177722     Medline TA:  Horm Metab Res     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  842-7     Citation Subset:  IM    
Department of Internal Medicine, School of Medicine of Ribeirao Preto, Sao Paulo, Brazil.
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MeSH Terms
Adrenocorticotropic Hormone / blood
Body Weight / physiology
Corticosterone / blood
Eating / physiology*
Fasting / physiology*
In Situ Hybridization
Insulin / blood
Leptin / blood
Melanocyte-Stimulating Hormones / blood
RNA, Messenger / biosynthesis,  genetics
Rats, Wistar
Receptor, Melanocortin, Type 4 / biosynthesis*
Reg. No./Substance:
0/Leptin; 0/RNA, Messenger; 0/Receptor, Melanocortin, Type 4; 11061-68-0/Insulin; 50-22-6/Corticosterone; 9002-60-2/Adrenocorticotropic Hormone; 9002-79-3/Melanocyte-Stimulating Hormones

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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