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

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (4) Citing Articles via Google Scholar Google Scholar Articles by Corporeau, C. Articles by Delarue, J. Search for Related Content PubMed Articles by Corporeau, C. Articles by Delarue, J.

Adipose tissue compensates for defect of phosphatidylinositol 3'-kinase induced in liver and muscle by dietary fish oil in fed rats

¹Equipe d’Accueil 948 "Oxylipides", Faculté de Médecine, Brest; ²Laboratoire d’Endocrinologie de la Nutrition, Faculté des Sciences, Orsay; and ³Département Génie Alimentaire, Ifremer, Nantes, France

Submitted 5 May 2005 ; accepted in final form 14 July 2005

The present work aimed to study in rats whether substitution of a low level of fish oil (FO; 2.2% of calories) into a low-fat diet (6.6% of calories from fat as peanut-rape oil or control diet) 1) has a tissue-specific effect on insulin signaling pathway and 2) prevents dexamethasone-induced alteration of insulin signaling in liver, muscle, and adipose tissue. Sixteen rats were used for study of insulin signaling, and sixteen rats received an oral glucose load (3 g/kg). Eight rats/group consumed control diet or diet containing FO over 5 wk. Four rats from each group received a daily intraperitoneal injection of saline or dexamethasone (1 mg·kg^–1·day^–1) for the last 5 days of feeding. In liver, FO decreased phosphatidylinositol 3'-kinase (PI 3'-kinase) activity by 54% compared with control diet. A similar result was obtained in muscle. In both liver and muscle, FO clearly amplified the effect of dexamethasone. FO did not alter early steps of insulin signaling, and in muscle GLUT4 protein content remained unaltered. In adipose tissue, FO increased PI 3'-kinase activity by 74%, whereas dexamethasone decreased it by 65%; inhibition of PI 3'-kinase activity by dexamethasone was similar in rats fed FO or control diet, and GLUT4 protein content was increased by 61% by FO. Glycemic and insulinemic responses to oral glucose were not modified by FO. In conclusion, FO increased PI 3'-kinase activity in adipose tissue while inhibiting it in liver and muscle. The maintenance of whole body glucose homeostasis suggests an important role of adipose tissue for control of glucose homeostasis.

eicosapentaenoic acid; docosahexaenoic acid; insulin resistance; polyunsaturated fatty acids

This article has been cited by other articles:

				C. Le Foll, C. Corporeau, V. Le Guen, J.-P. Gouygou, J.-P. Berge, and J. Delarue Long-chain n-3 polyunsaturated fatty acids dissociate phosphorylation of Akt from phosphatidylinositol 3'-kinase activity in rats Am J Physiol Endocrinol Metab, April 1, 2007; 292(4): E1223 - E1230. [Abstract] [Full Text] [PDF]

				D. Qi and B. Rodrigues Glucocorticoids produce whole body insulin resistance with changes in cardiac metabolism Am J Physiol Endocrinol Metab, March 1, 2007; 292(3): E654 - E667. [Abstract] [Full Text] [PDF]