Influence of naloxone, atropine, and metoclopramide on ethanol augmentation of insulin secretion after intravenous glucose stimulation.

The effect of naloxone (opiate antagonist), atropine (muscarinic antagonist), and metoclopramide (dopamine antagonist) upon ethanol augmentation of insulin secretion after intravenous glucose stimulation was studied in 19 young healthy subjects. Intravenous glucose tolerance tests were performed with and without pretreatment with oral ethanol. The effect of naloxone, atropine, and metoclopramide on insulin secretion was investigated in six, six, and seven subjects, respectively. Ethanol pretreatment was followed by increased insulin (p less than 0.001) and C-peptide areas (p less than 0.01) after intravenous glucose (0-10 min), indicating that ethanol augments insulin secretion. Neither antagonism with naloxone nor with atropine or metoclopramide was able to suppress the ethanol augmentation of insulin secretion. The decline in glucagon concentration normally seen after intravenous glucose administration was partially prevented by ethanol pretreatment.