Physical training in hyperplastic obesity. V. Effects of atropine on plasma insulin.

Ten hyperplastic obese women were trained physically on an ad-libitum diet preventing them from losing weight. Plasma-insulin concentrations decreased during oral glucose-tolerance test (OGTT), an effect which was more clearly seen after atropine administration. After intravenous-glucose administration (IVGTT) these effects were absent or much smaller. Insulin secretion stimulated by the sight and smell of food (CIS) was more pronounced after training, this increase being abolished by atropine. Physical training produces vagotony with well-known effects on circulatory variables such as a slower resting heart rate. Both the results after OGTT and CIS show the effects of increased vagotony also on insulin secretion. This effect tends to hide the insulin-concentration-lowering effect of physical training. This consequence of training is possibly dependent on enteric factors associated with insulin secretion since it was not found after IVGTT.