Studies on posthypoglycemic insulin resistance in insulin-dependent diabetes mellitus

Altogether 54 male patients with insulin-dependent diabetes mellitus participated in the studies. The impact of insulin-induced hypoglycemia on posthypoglycemic insulin sensitivity was evaluated for up to 12 hours following nadir hypoglycemia. The effect on glucose homeostasis following transient elevation of counterregulatory hormones was studied by exogenous administration of adrenaline, adreno-corticotropic hormone and growth hormone and by suppression of the endogenous release of growth hormone in connection with hypoglycemia. The studies were performed in the fasting state preceded by a 24 hour intravenous insulin infusion in order to avoid interference of subcutaneous insulin. Insulin resistance was determined by a constant rate intravenous infusion of somatostatin, insulin and glucose. This test seemed appropriate for the evaluation of total insulin resistance, and its reproducibility was acceptable. By using this method it was demonstrated that insulin resistance occurred for at least 12 hours after a hypoglycemic event in patients with IDDM, and that adrenaline caused immediate insulin resistance which, however, faded out within four to six hours, while GH exerted no immediate effect on insulin sensitivity but caused marked and sustained insulin resistance after a lag period of about four hours. Cortisol had no apparent effect within six hours but enhanced the effect of GH. The magnitude of these diabetogenic effects of hypoglycemia and GH was less pronounced in patients who already were more insulin resistant. These results are compatible with the idea that adrenaline is of major importance for the counterregulation and restoration of blood glucose during the first few hours following hypoglycemia, while GH is responsible for the induction of a long-lasting state of insulin resistance. It is possible that such prolonged insulin resistance may cause posthypoglycemic hyperglycemia in patients with IDDM. These studies therefore indicate that the GH suppressing hormone somatostatin may be of clinical value as an adjunct to insulin in the treatment of patients with insulin-dependent diabetes mellitus and labile blood glucose control.