Effects of fasting and refeeding on body mass, thermogenesis and serum leptin in Brandt's voles (Lasiopodomys brandtii)

(1)To investigate the effect of fasting and refeeding on the body mass, thermogenesis and serum leptin in Brandt's voles, the changes in body and body fat mass, resting metabolic rate (RMR), mitochondrial cytochrome c oxidase (COX) activity in liver and brown adipose tissue (BAT), uncoupling protein 1 (UCP1) content of BAT, serum leptin level and post-fasting food intake were monitored and measured.(2)Fasting induced significant reduction in body mass and body fat mass. Body mass can be restored to the control level in refeeding voles except for the body fat.(3)RMR decreased significantly in response to fasting, and can return to the control level after refeeding. Fasting induced significant reduction in total, but not specific, COX activity (nmol O2/min/total tissue) in liver and BAT, and UCP1 content in BAT, which was reversed after refeeding of 48h.(4)Fasting for 12h induced a rapid reduction in serum leptin content. There were no post-fasting compensatory increases in food intake. Interestingly, Brandt's voles did not recover adipose tissue mass, nor serum leptin levels, on refeeding.(5)Our data indicate that Brandt's voles can adjust their physiological functions integratively to cope with the starvation by the means of decreasing body mass, adaptive thermogenesis and serum leptin levels. There is no post-fasting hyperphagia in Brandt's voles. The reduction of serum leptin was somewhat earlier than the decline in body fat and body mass.