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Horm Metab Res 2002; 34(11/12): 686-690
DOI: 10.1055/s-2002-38264
Original Clinical
© Georg Thieme Verlag Stuttgart · New York

Effects of Fatty (fa) Allele and High-Fat Diet on Adipose Tissue Leptin and Lipid Metabolism

Y.-R.  Heo 1 , K.  Claycombe 2 , B.  H.  Jones 3 , P.  Wright 1 , G.  E.  Truett 1 , M.  Zemel 1 , W.  Banz 1 , M.  Maher 1 , N.  Moustaid-Moussa 1
  • 1 University of Tennessee, Department of Nutrition, Knoxville, TN, USA
  • 2 Michigan State University, Department of Food Science and Nutrition, MI, USA
  • 3 Life Science Division, Oak Ridge National Lab. Oak Ridge, TN, USA
Further Information

Publication History

Received 1 October 2002

Accepted after revision 26 November 2002

Publication Date:
27 March 2003 (online)

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Abstract

Leptin is an adipocyte-secreted hormone that binds hypothalamic receptors and potently decreases food intake. Leptin receptor defects in homozygous mutant Zucker fatty (fa/fa) rats lead to massive obesity, hyperphagia, decreased energy expenditure, and insulin resistance, while the phenotype of heterozygous (Fa/fa) lean rats lies between lean (Fa/Fa) and obese (fa/fa) rats. Whether heterezygotes exhibit specific changes in lipid metabolism in a diet-responsive manner is not clear. Thus, the specific aim of this study was to test whether the presence of one fa allele modulates lipid metabolism and leptin, and whether these effects are exacerbated by high-fat diet. We demonstrate that the presence of one fa allele significantly increases lipogenesis in adipose tissue assessed by glycerol-3-phosphate dehydrogenase (GPDH) and fatty acid synthase (FAS) activities. FAS is more responsive to high-fat diets than GPDH in Fa/fa rats. Adipose tissue leptin levels are significantly higher in fat pads of Fa/fa compared to Fa/Fa rats. Moreover, Fa/fa rats fed high-fat diet show an additional two-fold increase in leptin levels compared to wild type rats on the same diet. Collectively, these results indicate that the presence of one fa allele increase adipocyte lipogenic enzyme activities, which results in hyperleptinemia concurrent with increased adiposity.

Key words

Obesity - Fatty Acid Synthase - Glycerol-3-Phosphate Dehydrogenase - Lipogenic Enzyme

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N. Moustaid-Moussa, Ph.D.

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