Effect of exercise on food intake regulating hormones

Ghrelin, a peptide hormone identified in the stomach, is directly involved with the regulation of energy balance and obesity. Acylation of ghrelin is essential for appetite regulation. This study examined the effect of exercise on acylated ghrelin and leptin consantration in highly trained athletes. Seven male subjects aged 18-21 yr participated in two, 4-h trials (exercise and control) in a random crossover design. Trials began at 0900 in the morning after an overnight fast. In the exercise trial, subject ran for 105 min at 50% of maximal oxygen uptake and 15 min at 70% of maximal oxygen uptake between 0900 and 1100. After this, they rested for 2 h and consumed a test meal at 1200. In the control trial, subjects rested for 4 h and consumed a test meal at 1200. Blood samples were collected at 0, 1, 2, 3 and 4 h. The data were analysed using one - way repeated- measures analysis of variance. Plasma acylated ghrelin values were significantly increased (p<0.05) and serum leptin values were significantly decreased (p<0.05) immediately after the 60 min. exercise, while there were no changes in plazma acylated ghrelin and serum leptin levels immediately after the 120 min. exercise. These results suggest that acute negative energy balance induced by 60 min. moderate aerobic exercise elicits a metabolic response with opposite changes in acylated ghrelin and leptin concentrations in male athletes.Key Words: acylated ghrelin, energy homeostasis, leptin