Lessons from animal models of obesity

Obesity in animals may result from genetic, dietary, or neuroendocrine perturbations. Study of these models has identified the central systems that regulate food intake and energy expenditure and identified the interdependence of feeding behavior, the autonomic nervous system, and adrenal glucocorticoids in the development of obesity. The animal models of obesity have been influential in showing that adipose tissue is an important secretory tissue. The recent identification of five genes that cause obesity will provide new insight into the physiologic systems that regulate energy balance.