Although several possible mechanisms exist by which the pancreatic hormone, insulin, could enter the brain from the blood, most evidence suggests that the majority of it enters primarily by a receptor-mediated transport process. Many factors influence the rate of entry, including fasting and refeeding and several pathological conditions. Within the brain insulin acts on specific receptors to influence a number of behaviors, and especially caloric homeostasis and cognition.

Insulin, Blood-Brain Barrier, homeostasis

Department of Psychiatry, Box 670559, University of Cincinnati, Cincinnati, OH 45267-0559, USA