Short-term or long-term intracerebroventricular (i.c.v.) infusion of insulin exhibits a discrete anabolic effect on cerebral energy metabolism in the rat.

Evidence for an involvement of insulin in the regulation of cerebral glycolytic glucose catabolism is becoming more and more convincing. To investigate whether short-term or long-term administration of insulin to the brain influences brain energy metabolism, we determined tissue concentrations of energy-rich phosphates in cerebral parietotemporal cortex and in hippocampus of 1- (adult) and 2-year-old (aged) male Wistar rats treated with intracerebroventricular (i.c.v.) infusion of the hormone for 1, 7, and 21 days. In cerebral parietotemporal cortex, tissue concentrations of ATP, PCr, ADP, ATP/ADP ratio and energy charge potential were all unaltered. In hippocampus, however, the concentration of PCr was significantly increased. Thus, short-term and long-term i.c.v. administration of insulin are assumed to have a discrete anabolic effect on the cerebral energy pool.