Plasma glucagon in simple obesity: effect of exercise

Obesity is uniformly associated with hyperinsulinemia, but studies of glucagon have produced conflicting results. We have studied glucagon, insulin, and growth hormone levels in response to a submaximal exercise in a group of normal and obese nondiabetic women. Basal plasma insulin levels were higher in the obese women and remained so throughout the experiment. Fasting and post exercise glucagon levels were similar in both groups. Basal growth hormone levels were lower in the obese group and remained suppressed, whereas a significant increase in growth hormone levels was observed among normal women in response to exercise. We conclude that in response to a submaximal exercise the glucagon levels in obese women are not different compared to normal, despite hyperinsulinemia and suppressed growth hormone levels in the former.