HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 282, Issue 39, 28465-28473, September 28, 2007

This Article Full Text Full Text (PDF) All Versions of this Article: 282/39/28465    most recent M705503200v1 Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Kang, L. Articles by Nagy, L. E. Search for Related Content PubMed PubMed Citation Articles by Kang, L. Articles by Nagy, L. E. Social Bookmarking                      What's this?

Chronic Ethanol and Triglyceride Turnover in White Adipose Tissue in Rats

INHIBITION OF THE ANTI-LIPOLYTIC ACTION OF INSULIN AFTER CHRONIC ETHANOL CONTRIBUTES TO INCREASED TRIGLYCERIDE DEGRADATION^*

Li Kang, Xiaocong Chen^¶, Becky M. Sebastian, Brian T. Pratt, Ilya R. Bederman^¶, James C. Alexander^||, Stephen F. Previs^¶, and Laura E. Nagy^**¶1

From the Departments of Biochemistry, ^||Mathematics, and ^¶Nutrition, Case Western Reserve University, Cleveland, Ohio 44106 and Departments of ^**Gastroenterology and Pathobiology, Cleveland Clinic Foundation, Cleveland, Ohio 44195

Chronic ethanol consumption disrupts whole-body lipid metabolism. Here we tested the hypothesis that regulation of triglyceride homeostasis in adipose tissue is vulnerable to long-term ethanol exposure. After chronic ethanol feeding, total body fat content as well as the quantity of epididymal adipose tissue of male Wistar rats was decreased compared with pair-fed controls. Integrated rates of in vivo triglyceride turnover in epididymal adipose tissue were measured using ²H₂O as a tracer. Triglyceride turnover in adipose tissue was increased due to a 2.3-fold increase in triglyceride degradation in ethanol-fed rats compared with pair-fed controls with no effect of ethanol on triglyceride synthesis. Because increased lipolysis accompanied by the release of free fatty acids into the circulation is associated with insulin resistance and liver injury, we focused on determining the mechanisms for increased lipolysis in adipose tissue after chronic ethanol feeding. Chronic ethanol feeding suppressed -adrenergic receptor-stimulated lipolysis in both in vivo and ex vivo assays; thus, enhanced triglyceride degradation during ethanol feeding was not due to increased -adrenergic-mediated lipolysis. Instead, chronic ethanol feeding markedly impaired insulin-mediated suppression of lipolysis in conscious rats during a hyperinsulinemic-euglycemic clamp as well as in adipocytes isolated from epididymal and subcutaneous adipose tissue. These data demonstrate for the first time that chronic ethanol feeding increased the rate of triglyceride degradation in adipose tissue. Furthermore, this enhanced rate of lipolysis was due to a suppression of the anti-lipolytic effects of insulin in adipocytes after chronic ethanol feeding.

Received for publication, July 5, 2007 , and in revised form, August 7, 2007.

^* This work was supported by National Institutes of Health Grant AA 11876. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

¹ To whom correspondence should be addressed: Dept. of Gastroenterology and Pathobiology, Cleveland Clinic Foundation, Lerner Research Institute/NE40, 9500 Euclid Ave., Cleveland, OH 44195. Tel.: 216-444-4021; Fax: 216-636-1493; E-mail: laura.nagy{at}case.edu.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?