Dietary (n-3) and (n-6) Polyunsaturated Fatty Acids Rapidly Modify Fatty Acid Composition and Insulin Effects in Rat Adipocytes

Manuscript received 12 November 1996. Initial reviews completed 8 January 1997. Revision accepted 23 November 1997.

Maria Fickova^*, Pierre Hubert, Gérard Crémel^, , and Claude Leray^**

^* Institute of Experimental Endocrinology, Slovak Academy of Sciences, 83306 Bratislava, Slovakia;  INSERM U. 338, F-67084 Strasbourg, France; and ^** INSERM U. 311, F-67065 Strasbourg, France

The influence of dietary (n-3) compared with (n-6) polyunsatured fatty acids (PUFA) on the lipid composition and metabolism of adipocytes was evaluated in rats over a period of 1 week. Isocaloric diets comprised 16.3 g/100 g protein, 53.8 g/100 g carbohydrate and 21.4 g/100 g lipids, the latter containing either (n-3) PUFA (32.4 mol/100 mol) or (n-6) PUFA (37.8 mol/100 mol) but having identical contents of saturated, monounsaturated and total unsaturated fatty acids and identical polyunsaturated to saturated fatty acid ratios and double bond indexes. Despite comparable food intake, significantly smaller body weight increments and adipocyte size were observed in rats of the (n-3) diet group after feeding for 1 wk. Rats fed the (n-3) diet also had significantly lower concentrations of serum triglycerides, cholesterol and insulin compared with those fed the (n-6) diet, although levels of serum glucose and free fatty acids did not differ in the two dietary groups. In the (n-6) diet group, the (n-6) and (n-3) PUFA contents of plasma triglycerides, free fatty acids and phospholipids were 30-60% higher and 60-80% lower, respectively, than in the (n-3) diet group, whereas adipocyte plasma membrane phospholipids showed a significantly higher unsaturated to saturated fatty acid ratio and greater fluidity. Glycerol release in response to noradrenaline was significantly higher in the adipocytes of rats fed the (n-3) diet, whereas the antilipolytic effect of insulin generally did not differ in the two groups. Finally, insulin stimulated the transport of glucose and its incorporation into fatty acids to a lesser extent in adipocytes of (n-3) diet fed rats compared with (n-6) diet fed rats. This reduction in the metabolic effects of insulin in rats fed a (n-3) diet for 1 wk could be related to smaller numbers and a lower binding capacity of the insulin receptors on adipocytes and/or to a lesser degree of phosphorylation of the 95 kDa beta subunit of the receptor. In conclusion, dietary intake for 1 wk of (n-3) rather than (n-6) PUFA is sufficient to induce significant differences in the lipid composition and metabolic responses to insulin of rat adipocytes.

The Journal of Nutrition Vol. 128 No. 3 March 1998, pp. 512-519
Copyright ©1998 by the American Society for Nutritional Sciences

This article has been cited by other articles:

				C. I. O'Connor, L. M. Lawrence, and S. H. Hayes Dietary fish oil supplementation affects serum fatty acid concentrations in horses J Anim Sci, September 1, 2007; 85(9): 2183 - 2189. [Abstract] [Full Text] [PDF]

				M. A. Schirmer and S. D. Phinney {gamma}-Linolenate Reduces Weight Regain in Formerly Obese Humans J. Nutr., June 1, 2007; 137(6): 1430 - 1435. [Abstract] [Full Text] [PDF]

				D. Mozaffarian, A. Ascherio, F. B. Hu, M. J. Stampfer, W. C. Willett, D. S. Siscovick, and E. B. Rimm Interplay Between Different Polyunsaturated Fatty Acids and Risk of Coronary Heart Disease in Men Circulation, January 18, 2005; 111(2): 157 - 164. [Abstract] [Full Text] [PDF]

				E. E. D. Felton and M. S. Kerley Performance and carcass quality of steers fed whole raw soybeans at increasing inclusion levels J Anim Sci, March 1, 2004; 82(3): 725 - 732. [Abstract] [Full Text] [PDF]

				L. Wang, A. R Folsom, Z.-J. Zheng, J. S Pankow, and J. H Eckfeldt Plasma fatty acid composition and incidence of diabetes in middle-aged adults: the Atherosclerosis Risk in Communities (ARIC) Study Am. J. Clinical Nutrition, July 1, 2003; 78(1): 91 - 98. [Abstract] [Full Text] [PDF]

				K-L. C. Jen, A. Buison, M. Pellizzon, F. Ordiz Jr., L. Santa Ana, and J. Brown Differential Effects of Fatty Acids and Exercise on Body Weight Regulation and Metabolism in Female Wistar Rats Experimental Biology and Medicine, July 1, 2003; 228(7): 843 - 849. [Abstract] [Full Text] [PDF]

				M. Korotkova, B. Gabrielsson, M. Lonn, L.-A. Hanson, and B. Strandvik Leptin levels in rat offspring are modified by the ratio of linoleic to {alpha}-linolenic acid in the maternal diet J. Lipid Res., October 1, 2002; 43(10): 1743 - 1749. [Abstract] [Full Text] [PDF]

				V. M Rodriguez, M. P Portillo, C. Pico, M T. Macarulla, and A. Palou Olive oil feeding up-regulates uncoupling protein genes in rat brown adipose tissue and skeletal muscle Am. J. Clinical Nutrition, February 1, 2002; 75(2): 213 - 220. [Abstract] [Full Text] [PDF]

				S. P. Poulos, M. Sisk, D. B. Hausman, M. J. Azain, and G. J. Hausman Pre- and Postnatal Dietary Conjugated Linoleic Acid Alters Adipose Development, Body Weight Gain and Body Composition in Sprague-Dawley Rats J. Nutr., October 1, 2001; 131(10): 2722 - 2731. [Abstract] [Full Text] [PDF]

				J. J. Wilkes, A. Bonen, and R. C. Bell A modified high-fat diet induces insulin resistance in rat skeletal muscle but not adipocytes Am J Physiol Endocrinol Metab, October 1, 1998; 275(4): E679 - E686. [Abstract] [Full Text] [PDF]

				M. Taouis, C. Dagou, C. Ster, G. Durand, M. Pinault, and J. Delarue N-3 Polyunsaturated fatty acids prevent the defect of insulin receptor signaling in muscle Am J Physiol Endocrinol Metab, March 1, 2002; 282(3): E664 - E671. [Abstract] [Full Text] [PDF]