Nocturnal growth hormone surges in type 1 diabetes mellitus are both sleep- and glycemia-dependent: assessment under continuous sleep monitoring.

Our work has studied the relationship between nocturnal growth hormone (GH) surges, sleep and glycemia in seven conventionally treated type 1 diabetic patients under continuous sleep monitoring and the results were compared to those found in five age-matched healthy controls. On the experimental day, sleep was monitored from 24.00 to 07.00. Blood glucose levels and GH were assayed in both groups. As a group the diabetics had nocturnal GH responses higher than those in controls. However, the sleep-related GH release is not abnormally high in patients who maintain strict normoglycemia. Early-night hypoglycemia and/or rapidly decreasing blood glucose concentrations enhance sleep-related GH secretion in diabetics, whereas hypoglycemia not associated with slow-wave sleep (SWS) causes a moderate increase in GH. Late-onset nocturnal hypoglycemia is not potent enough to stimulate GH. It is proposed that in diabetics sleep-related GH production is probably not abnormally elevated within a wide range of stable glucose levels, but when these thresholds are crossed or when there is a rapid decrease in blood glucose, then GH secretion is inversely related to the changing blood glucose. Therefore, our study supports the conclusion that sleep-related GH secretion is finely modulated by the actual glycemic fluctuations in diabetic patients.