Document Detail


Site-specific effects of sympathectomy on the adrenergic control of lipolysis in hamster fat cells.
MedLine Citation:
PMID:  7671187     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Regional variations in the response of adipose tissue to lipolytic stimuli have been suggested to be involved in the development of visceral adiposity-related morbidity and mortality. Moreover, studies in humans and in laboratory rodents such as hamsters have shown that the response of adipocytes to catecholamines depends on their anatomical origin. The aim of the present study was to investigate the relative involvement of the adrenal medulla and of the sympathetic nervous system on regional differences in the adrenergic control of lipolysis in isolated adipocytes from inguinal and epididymal adipose tissues. For this purpose, we carried out adrenal demedullation or chemical sympathectomy in hamsters. The results confirmed that epididymal adipocytes were significantly more responsive to to a beta-adrenergic stimulation than inguinal adipocytes (p < or = 0.05). This site specificity could originate at a step distal to receptors since tissues exhibited a similar number of binding sites for [125I]cyanopindolol. No significant regional differences were observed in the alpha2-adrenergic antilipolytic response, with the exception of the clonidine EC50. A 14-day sympathectomy significantly increased the beta-adrenergic lipolytic response only in inguinal adipocytes (p < or = 0.05), and increased the alpha2-adrenergic response only in epididymal adipocytes (p < or = 0.05). On the other hand, adrenal demedullation had no effect on both adrenergic pathways. These results suggest that the sympathetic tone of adipose tissues could be involved in the alpha2- and beta-adrenergic site-specific response in hamster fat cells. The 33% increase of the beta-response in inguinal fat cells and the 38% increase of the alpha2-response in epididymal fat cells also suggest that the sympathetic pathway favors the lipolytic activation of the epididymal adipose tissue.
Authors:
J Robidoux; P Pirouzi; J Lafond; R Savard
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Canadian journal of physiology and pharmacology     Volume:  73     ISSN:  0008-4212     ISO Abbreviation:  Can. J. Physiol. Pharmacol.     Publication Date:  1995 Apr 
Date Detail:
Created Date:  1995-10-16     Completed Date:  1995-10-16     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0372712     Medline TA:  Can J Physiol Pharmacol     Country:  CANADA    
Other Details:
Languages:  eng     Pagination:  450-8     Citation Subset:  IM    
Affiliation:
Département des sciences biologiques, Université du Québec à Montréal, Canada.
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MeSH Terms
Descriptor/Qualifier:
Adipocytes / metabolism*
Adrenal Medulla / physiology
Animals
Cell Membrane / metabolism
Cricetinae
Epididymis / metabolism
Epinephrine / metabolism
Lipolysis / physiology*
Male
Mesocricetus
Norepinephrine / metabolism
Oxidopamine
Radioligand Assay
Receptors, Adrenergic, alpha-2 / metabolism
Receptors, Adrenergic, beta / metabolism
Sympathectomy*
Sympathectomy, Chemical
Sympathetic Nervous System / physiology*
Chemical
Reg. No./Substance:
0/Receptors, Adrenergic, alpha-2; 0/Receptors, Adrenergic, beta; 1199-18-4/Oxidopamine; 51-41-2/Norepinephrine; 51-43-4/Epinephrine

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