Peptidergic control of insulin-induced feeding.

Subcutaneous administration of insulin(10 U/kg) produced hypoglycemia in rats with a concomitant induction of feeding. The opiate antagonist naloxone failed to alter food ingestion following insulin administration when quantitated over a 3-hour period; however, naloxone (20 mg/kg) significantly suppressed eating during the first hour of the study. Starvation-induced feeding was markedly suppressed by relatively low doses of naloxone (1 mg/kg). The dopamine antagonist haloperidol, the cholinergic antagonist atropine, and the putative satiety factors CCK-8, bombesin, histidyl-proline diketopiperazine and calcitonin suppressed insulin-induced feeding. Naloxone, CCK-8 and bombesin significantly raised blood glucose levels following insulin induced hypoglycemia.