SHORT-TERM OR LONG-TERM INTRACEREBROVENTRICULAR (ICV) 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.