Effect of moderate physical exercise on plasma and tissue levels of insulin-like growth factor–1 in adult rats

Abstract

The aim of the present study was to evaluate the influence of moderate physical exercise on muscle, liver, and plasma insulin-like growth factor–1 (IGF-1) levels and to analyze certain protein and carbohydrate metabolism patterns related to this physiological state. Adult male rats were subjected to physical exercise consisting of swimming for a period of 6 weeks. The animals were divided into two groups, a trained (T) and a sedentary (S) group, with both groups receiving a 12% casein diet. The following parameters were analyzed: body weight, food intake, muscle and liver weight, plasma IGF-1, glucose, insulin, urea and creatinine, muscle protein, glycogen, and muscle and liver IGF-1. Group T showed lower body weight, food intake, and glucose and insulin levels than group S. The other parameters did not differ between groups. These results suggest that moderate physical exercise does not alter IGF-1 levels and therefore cannot be considered a regulating factor of IGF-1 under these experimental conditions.