The Effect of Food Restriction on Appetite Regulating Hormones and Adiponectin Activity

ABSTRACT

We investigated the effects of short-term food restriction and repeated fasting and refeeding on appetite regulating hormones and adiponectin activity in rats. To investigate the acute and chronic effects of food restriction in vivo, Sprague-Dawley rats were divided into a control group (CON), a 1 day fasting group, a 2 days fasting gruop, a 3 days fasting gruop, a fasting and refeeding for 1 week gruoup and a fasting and refeeding for 2 weeks group. Blood glucose, triglyceride and total cholesterol decreased in all fasting groups compared to those in the CON group. Free fatty acid of all fasting groups was higher than those in the CON, and were lowest in the three cycle fasting and refeeding group. Blood insulin following short-term food restriction was lower than that in the CON. blood ghrelin increased significantly (p < 0.01) following the short-term food restriction, However, blood ghrelin in the repeated fasting and refeeding groups decreased significantly decreased (p < 0.01) compared to that in the CON and short-term food restriction group. In contrast, blood leptin decreased significantly (p < 0.01) in the short term food restriction group and the three cycle of fasting and refeeding group but increased in the six cycle of fasting and refeeding group. No significant differences in adiponectin contents were observed in the short-term food restriction group. But, adiponectin increased significantly (p < 0.01) following the fasting and refeeding cycles. Blood adiponectin and blood leptin levels were showed positively correlated (r2 = 0.469) when all samples were analysed together.