Loss of Ventromedial Hypothalamic Leptin Receptors Results in Increased Adiposity and a Metabolic Syndrome
Obesity is a leading health problem here in the United States and in other developing countries. Obesity is a risk factor for several life-threatening conditions including Type II diabetes, hypertension, and cardiovascular disease. Given the growing obesity epidemic, understanding the mechanisms whereby the central nervous system monitors and regulates energy homeostasis has become a major focus of scientific research in the last several decades. The discovery that mice fed a low fat diet exhibit significantly increased adipose mass with no difference in weight compared to wild-type littermates. Further, these mice exhibit a metabolic syndrome including mild steatosis, dyslipidemia, and hyperleptinemia. From a young age, Lepr KOleptin, an adipocyte-derived hormone, acts on the brain to suppress appetite and stimulate energy expenditure greatly extended our understanding of such mechanisms. The leptin receptor is expressed in a number of hypothalamic nuclei known to play a role in energy homeostasis. While much work has focused on leptin's actions in the arcuate nucleus, other sites have received substantially less attention. Here, I report that mice lacking leptin receptors within the ventromedial hypothalamic nucleus (Lepr KOVMH) develop increased adiposity and a metabolic syndrome. Lepr KOVMH mice fed high fat rodent chow show an increased sensitivity to diet-induced obesity, while Lepr KOVMH mice are hyperinsulinemic and eventually become glucose intolerant. These data demonstrate that Lepr KOVMH mice are a novel genetic model of obesity and may be used for the study of energy partitioning, lipogenesis, and central leptin signaling.