The ability of GH to decrease fatness and insulin-regulated events such as lipogenic enzyme activities is well known in pigs. Nevertheless, the precise mechanism underlying these actions has not been elucidated yet. Expression of the transcription factor sterol regulatory element binding protein (SREBP)-1 has been reported as a key mediator of insulin action in rat hepatocytes and adipose cell lines. The present study aimed to determine whether the regulation of lipogenesis by GH and/or insulin in porcine adipocytes also involved SREBP-1. Isolated adipocytes, obtained from perirenal or s.c. adipose tissue samples of female pigs (51+/-0.4 kg; n=17), were cultured in serum-free medium in the absence or presence of these hormones for up to 4 days. Glucose incorporation and fatty acid synthase activity were increased by insulin in a dose-dependent manner in adipocytes of both sites. The increase was maximal at 1.7 and 17 nM in s.c. and perirenal adipocytes respectively, suggesting inter-depot differences in the regulation of lipogenesis by insulin. These insulin-stimulated events were decreased by GH (1 nM). No change in SREBP-1 mRNA levels was observed in response to GH and/or insulin. Taken together, these data indicate that the regulation of lipogenesis by insulin and GH appears to not involve changes in SREBP-1 mRNA levels in porcine adipocytes.

This article has been cited by other articles:

				J. Demars, J. Riquet, M.-P. Sanchez, Y. Billon, J.-F. Hocquette, B. Lebret, N. Iannuccelli, J.-P. Bidanel, D. Milan, and F. Gondret Metabolic and histochemical characteristics of fat and muscle tissues in homozygous or heterozygous pigs for the body composition QTL located on chromosome 7 Physiol Genomics, August 20, 2007; 30(3): 232 - 241. [Abstract] [Full Text] [PDF]

				D. Gardan, F. Gondret, and I. Louveau Lipid metabolism and secretory function of porcine intramuscular adipocytes compared with subcutaneous and perirenal adipocytes Am J Physiol Endocrinol Metab, August 1, 2006; 291(2): E372 - E380. [Abstract] [Full Text] [PDF]

				F. Gondret, L. Lefaucheur, H. Juin, I. Louveau, and B. Lebret Low birth weight is associated with enlarged muscle fiber area and impaired meat tenderness of the longissimus muscle in pigs J Anim Sci, January 1, 2006; 84(1): 93 - 103. [Abstract] [Full Text] [PDF]