Impaired Insulin Secretion in Human Diabetes Mellitus: The Effect of Naloxone-Induced Opiate Receptor Blockade

Human diabetes mellitus is characterized by impaired insulin response to intravenous glucose. In search of possible factors which impair insulin release, we have investigated the effect of naloxone, a specific opiate receptor blocker, on insulin responses to glucose in subjects with non-insulin-dependent diabetes, as well as in normal subjects. Naloxone was given as a priming dose of 0.4 mg followed by a constant infusion of either 0.4 mg (N = 7), 2 mg (N = 7), or 4 mg (N = 8) for 90 min. Acute insulin response to glucose (mean change 3–10 min insulin), second phase insulin secretion (change 10–60 min), as well as glucose disappearance rates (﹪/min) were significantly increased in the diabetics receiving the two higher doses of naloxone (2 and 4 mg, respectively). None of these effects were seen in diabetics receiving saline or in normal subjects receiving naloxone. These results seem to suggest that sensitivity to endogenous opiates may play some part in non-insulin-dependent diabetes.