Naloxone attenuates recovery from insulin-induced hypoglycemia in normal man

The effect of the opioid antagonist, naloxone, on recovery of serum glucose concentrations from insulin-induced (0.1 U/kg) hypoglycemia was determined in five normal adult men. Each subject was studied on 2 separate days, at least 2 weeks apart, during an infusion of either normal saline (6.5 ml/h) or naloxone (0.8 mg/h). The order of the infusions was randomized and double blinded. Although glucose recovery was complete by 120 min after insulin administration during each study, the fractional rate of glucose recovery as determined by analysis of covariance was significantly slower during the naloxone infusions (P = 0.008). Plasma glucagon, serum cortisol, and serum GH concentrations were not different during glucose recovery on either study day. These studies suggest that endogenous opioids contribute to glucose recovery from insulin-induced hypoglycemia and therefore may be important to glucose homeostasis in normal man.