Effects of food restriction on body mass, thermogenesis and serum leptin level in Apodemus chevrieri (Mammalia: Rodentia: Muridae)

To investigate the effect of food restriction on the body mass, thermogenesis and serum leptin level in Apodemus chevrieri, the changes of body mass, body fat mass, resting metabolic rate (RMR), mitochondrial cytochrome coxidase (COX) activity both in liver and brown adipose tissue (BAT), uncoupling protein1 (UCP1) content of BAT, and serum leptin level were measured. The results showed that food restriction induced significant reductions in body mass and body fat mass. RMR decreased significantly in response to food restriction, and food restriction induced significant reduction in total mitochondrial protein content, COX activity both in liver and BAT, and UCP1 content in BAT. Food restriction also induced a reduction in serum leptin level. In contrast, length and mass with content in the small intestine in the food-restricted group was significantly higher relative to the control group. It suggests that the physiological regulations in energy metabolism to adaptively cope with a period of food shortage include decreasing body mass, reductions in the energy spent for RMR and thermogenesis, as well as the mobilization of fat storage. Leptin may play a potential role in physiological regulations in thermogenesis in response to food restriction.