Plasma growth hormone response to insulin-induced hypoglycemia in diabetes mellitus

Summary Plasma human growth hormone (HGH) response to insulin-induced hypoglycemia was studied in patients with diabetes mellitus and age and sex matched normal subjects. The diabetics comprised two groups: (a) those with retinopathy, (b) those without retinopathy. Adequate hypoglycemia (50% or a greater fall in fasting blood glucose) was achieved by i.v. administration of insulin 0.1 U/kg body weight in normal subjects and 0.2 U/kg in diabetics. Mean fasting plasma HGH levels did not differ significantly between control subjects (1.39 ± 0.25 SEM, ng/ml), diabetics without retinopathy (1.55 ± 0.25) and diabetics with retinopathy (1.81 ± 0.6). There was a significant rise in plasma HGH, following insulin-induced hypoglycemia in all three groups. When mean Δ HGH or sum HGH value in different groups were compared, no significant difference was observed. However, mean HGH-hypoglycemia index (Δ HGH · 100/nadir blood glucose) was significantly lower in the two diabetic groups as compared to that obtained in control subjects, but it was identical in diabetics with or without retinopathy. In 32% of diabetic patients abnormal blood glucose and plasma HGH responses were observed.