Effects of cold acclimation on body weight, serum leptin level, energy metabolism and thermogenesis in the Mongolian gerbil Meriones unguiculatus

摘要

To determine the adaptive strategy and the role of leptin in the regulation of body weight and energy balance, body weight, serum leptin level, body fat mass, energy intake, basal metabolic rate and nonshivering thermogenesis were measured after 3 weeks acclimation at 5°C for adult female Mongolian gerbils ( Meriones unguiculatus ) . Body mass was monitored every 3 days. Body fat content was analysed with the Soxhlet method. Energy intake was measured in food trials. Metabolic trials were conducted with closed-circuit respirometer and nonshivering thermogenesis was induced by injection of mass-dependent dosage of noradrenaline. Serum leptin concentration was measured with a commercial multispecies leptin RIAkit (Linco Company, USA). Results showed that: 1) no significant changes in body weight were found at 5°C; 2) serum leptin levels and body fat mass were lower at 5°C than that of control (23°C). There is a positive correlation between leptin concentration and body fat mass; 3) energy intake, basal metabolic rate, nonshivering thermogenesis were higher at 5°C than that of control. These results suggested that Mongolian gerbils enhanced thermogenic capacity and increased their maintenance cost during cold-acclimation, thus could cause the increase in energy intake. Leptin participated in the regulation of energy balance and body weight for Mongolian gerbils. However, it seemed that there was no direct relationship between serum leptin concentration and thermogenesis [ Acta Zoologica Sinica 50 (3): 334 - 340, 2004].