LEPTIN AND THE DEVELOPMENT OF OBESITY AND DIABETES IN PSAMMOMYS-OBESUS

The recently discovered ob gene and its circulating product, leptin, m ay be critical factors in the control of energy balance, Recent studie s in ob/ob mice, which lack circulating leptin, have shown dramatic re ductions in food intake and bodyweight after leptin treatment. In addi tion, studies in both humans with obesity and animal models of obesity have demonstrated hyperleptinemia, Here, we report a longitudinal stu dy examining changes in circulating leptin during the development of o besity and diabetes in Psammomys obesus. Over the 8 weeks of the study , lean animals increased their bodyweight by 154% and leptin levels re mained essentially unchanged, In contrast, animals that developed obes ity (223% increase in bodyweight), hyperglycemia, and hyperinsulinemia also developed hyperleptinemia between 4 weeks and 8 weeks of age, Th ese results demonstrate that the development of hyperleptinemia is ass ociated with the development of obesity and subsequent metabolic abnor malities.