Effects of ethanol on carbohydrate metabolism: I. Influence on oral glucose tolerance test

To study the effect of ethanol on glucose tolerance test, a series of experiments were performed on Sprague-Dawley male rats weighing 250 g. After 18-hr fast, each rat was given, at random, the following test substances (one test substance at a time) intragastrically in a volume of 0.5 ml/100 g body weight: saline; glucose 0.75 g/kg (3 kcal); ethanol 0.4 g/kg (3 kcal); and ethanol with glucose. Saline or ethanol alone produced no significant changes in blood glucose or plasma insulin concentrations. Addition of ethanol to glucose load resulted in glucose intolerance as well as a lower and sluggish insulin response when compared to these with glucose load alone. The results suggest that ethanol per se has no effect on blood glucose or plasma insulin. However, when given together with glucose load, ethanol produces glucose intolerance as well as inhibition of glucose mediated insulin response.