Lack of Post Prandial Exercise-Induced Growth Hormone Secretion in Normoglycemic Insulin-Treated Diabetic Men

Abstract

An exercise load (450 Kpm/min for 20 min; 75 W) was performed 4 hours after the beginning of the midday meal in 7 healthy men and in 6 insulin dependent diabetic men perfectly controlled. A rise in plasma HGH levels was observed in 6 out of the 7 healthy men: the mean maximal values were 6.3 ± 1.7 ng/ml 40 minutes after the beginning of the exercise (0.8 ± 0.6 ng/ml before it). No HGH secretion was observed during the 80 minutes of blood sampling in the 6 normoglycemic insulin-treated diabetic men with initial plasma HGH values of 1.0 ± 0.6 ng/ml. Mean plasma glucose values were identical in both groups during exercise. Plasma insulin assays were performed in the healthy subjects and in the 4 recently insulin treated diabetic subjects with no acquired insulin antibodies. The mean plasma insulin values observed in diabetics were about 2 times higher than in nondiabetics despite identical mean plasma glucose levels. It is suggested that this peripheral blood hyperinsulinism associated with normoglycemia may have blocked HGH secretion in these diabetic subjects submitted to exercise in the post prandial state.

Key words

Human Growth Hormone - Plasma Insulin - Blood Glucose - Insulin-Treated Diabetes - Exercise