Importance of growth hormone for blood glucose regulation following insulin-induced nocturnal hypoglycemia in insulin-dependent diabetes mellitus.
The effect of growth hormone (GH) on the glucose homeostasis following nocturnal hypoglycemia was studied between 4 a.m. and noon in eight male patients with insulin-dependent diabetes mellitus (IDDM) by a somatostatin (250 micrograms/h)-insulin (0.4 mU/kg/min)-glucose (6 mg/kg/min)-infusion test (SIGIT). The patients participated in two experiments in which hypoglycemia at 4 a.m. was induced by i.v. insulin (1.5 mU/kg/min). In both experiments the endogenous secretion of GH was suppressed by somatostatin (250 micrograms/h) and glucagon (0.5 ng/kg/min) was given as substitute for the somatostatin-induced suppression of endogenous glucagon secretion. GH (20 mU/kg/h) or saline was given for 60 min from nadir blood glucose in random order. Mean nadir glucose values were the same in both studies (1.7 +/- 0.2 vs. 1.7 +/- 0.1 mmol/l) and no differences were registered in plasma-free insulin, glucagon and the responses of adrenaline and cortisol to hypoglycemia. The infusion of GH resulted in plasma GH levels of about 50 micrograms/l at the end of the infusion, thereafter decreasing to low or immeasurable levels within 2 hours. Infusion of GH evoked a marked hyperglycemia within 4 hours. It is concluded that when hypoglycemia is accompanied by a transient increase in plasma GH, insulin resistance occurs after a lag period of approximately 4 hours and that this effect persists for at least another 4 hours.
D000328:Adult; D002940:Circadian Rhythm; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000188:drug therapy*; D005951:Glucose Tolerance Test; D013006:Growth Hormone / Q000008:administration & dosage* / Q000378:metabolism; D006801:Humans; D007003:Hypoglycemia / Q000097:blood*; D007328:Insulin / Q000008:administration & dosage; D007333:Insulin Resistance; D008297:Male; D013004:Somatostatin / Q000008:administration & dosage
D007328:Insulin; D013004:Somatostatin; D013006:Growth Hormone