Hypothalamic response to starvation: implications for the study of wasting disorders.

Weight loss is a potent stimulus to food intake in normal individuals. The persistence of anorexia in wasting disorders, therefore, implies a failure of this adaptive feeding response. We describe a model for the normal hypothalamic response to starvation composed of the stimulation of neuronal pathways that promote energy intake and storage coupled with the inhibition of pathways that exert opposing effects. This model provides a framework for investigating disturbances of the normal hypothalamic response to weight loss and suggests a specific mechanism by which cytokines contribute to wasting in acquired immune deficiency syndrome and other cachexic disorders.