The Effects of Exercise- and Food Intake Restriction-induced Weight Loss on the Expression of Ghrelin in Plasma and Stomach of Obese Rats / 中国运动医学杂志

ABSTRACT

Objective To clarify the effects of exercise- and food intake restriction-induced weight reduction on expression of ghrelin in plasma and stomach of obese rats,and to explore the role of ghrelin during weight loss. Methods 100 weaned Sprague-Dawley(SD) rats were randomly divided into control group(fed with standard chow,n= 20) and model group (two-bottle-feeding method,fed with standard chow and high-fat diet simultaneously, n=80). After 20 weeks feeding, Lee' s index of control was used as the reference of diet-induced obesity identification, and then diet-induced obese rats were randomly divided into four groupsobese control group,swimming group,food intake restriction group and swimming+food intake restriction group, eight rats in each group. Rats in swimming group underwent long-term(40 min,6 days/week for 5 weeks)swimming exercise. Calorie in food intake restriction group was restricted 1/3 of normal kcal for 3 weeks,and subsequently restricted 1/3 for 2 weeks. Swimming+food restriction group had the same intervention as swimming and food restriction group. 8 normal diet rats were also chosen as controls. After five weeks of treatments,peripheral fat mass of testis and kidney,ghrelin proteins in plasma and stomach,and ghrelin mRNA in stomach were measured. Results Gastric ghrelin protein and mRNA were significantly lower in obese control group than those in normal control group (P0.05). Compared with obese control group,weight and fat mass in all weight loss groups declined notablely(P<0.05);in swimming and swimming+food restriction groups,the expression of ghrelin protein or mRNA in plasma or stomach increased remarkably( P<0.05); in food restriction group, the level of ghrelin mRNA raised significantly (P<0.05), while ghrelin protein in plasma and stomach had not change. Conclusion The level of ghrelin increased in exercise induced weight loss,while showed no significant change in food intake restriction group, suggested that ghrelin might be involved in the process of weight loss induced by exercise.