M Szulinska1, K Musialik, J Suliburska, I Lis, P Bogdanski. 1. Department of Internal Medicine, Metabolic Disorders and Hypertension, Poznan University of Medical Sciences, Poznan, Poland. pawelbogdanski@wp.pl.
Abstract
BACKGROUND: Understanding the mechanism of development of the insulin resistance associated with obesity is crucial in identifying new therapeutic options for obese patients. AIM: The aim of this study was to examine the effects of L-arginine on the secretion of resistin in the context of insulin resistance in animal models. MATERIALS AND METHODS: 30 male and female Wistar rats were assigned to three equal groups: the standard diet group, the high-fat diet group, and the high-fat diet supplemented with L-arg group. After 6 weeks, the weight of the rats was measured. The animals were euthanized. The relative weight of the perirenal fat was determined and blood samples were taken for serum glucose, insulin, NO, and resistin. Insulin resistance was estimated using homeostasis model assessment (HOMA). RESULTS: It was found that the absolute and relative masses of the perirenal fat were significantly higher in rats fed the high-fat diet than in the control group. In rats on the high-fat diet supplemented with L-arginine, a tendency for perirenal fat to decrease was observed. The high-fat diet resulted in significant increases in glucose and insulin concentrations, and L-arginine supplementation significantly ameliorated the increase in both glucose and insulin. Moreover, significant decreases in NO concentration were seen in rats fed the high-fat diet. L-arginine supplementation protected significantly against increased NO concentration. Increases in HOMA-IR level and in resistin concentrations were observed in rats fed the high-fat diet. L-arginine supplementation partially restored HOMA-IR levels to those of the control group and did not influence resistin concentration. CONCLUSIONS: L-arginine supplementation improves insulin sensitivity in rats fed a high-fat diet, independently of resistin activity.
BACKGROUND: Understanding the mechanism of development of the insulin resistance associated with obesity is crucial in identifying new therapeutic options for obesepatients. AIM: The aim of this study was to examine the effects of L-arginine on the secretion of resistin in the context of insulin resistance in animal models. MATERIALS AND METHODS: 30 male and female Wistar rats were assigned to three equal groups: the standard diet group, the high-fat diet group, and the high-fat diet supplemented with L-arg group. After 6 weeks, the weight of the rats was measured. The animals were euthanized. The relative weight of the perirenal fat was determined and blood samples were taken for serum glucose, insulin, NO, and resistin. Insulin resistance was estimated using homeostasis model assessment (HOMA). RESULTS: It was found that the absolute and relative masses of the perirenal fat were significantly higher in rats fed the high-fat diet than in the control group. In rats on the high-fat diet supplemented with L-arginine, a tendency for perirenal fat to decrease was observed. The high-fat diet resulted in significant increases in glucose and insulin concentrations, and L-arginine supplementation significantly ameliorated the increase in both glucose and insulin. Moreover, significant decreases in NO concentration were seen in rats fed the high-fat diet. L-arginine supplementation protected significantly against increased NO concentration. Increases in HOMA-IR level and in resistin concentrations were observed in rats fed the high-fat diet. L-arginine supplementation partially restored HOMA-IR levels to those of the control group and did not influence resistin concentration. CONCLUSIONS:L-arginine supplementation improves insulin sensitivity in rats fed a high-fat diet, independently of resistin activity.