Beta-adrenoceptor blocking agents induce different counter-regulatory responses to insulin.

Simultaneous treatment with antidiabetic drugs and beta-adrenoceptor blocking agents is frequent on account of the high incidence of diabetes and cardiovascular disease. The effects of oral doses of pindolol, metoprolol, and propranolol on the response to insulin-induced hypoglycemia and an oral glucose load were investigated. During hypoglycemia metoprolol and propranolol inhibited the clearance of insulin (2 p less than 0.01) and caused a delay of glucose nadirs. This was not observed after pindolol. Epinephrine secretion and the counterregulatory response of growth hormone, ACTH and cortisol during hypoglycemia was significantly increased following metoprolol and propranolol but not after pindolol. The hypoglycemic symptoms and signs showed a prevalence of sweating and prolonged changes in skin conductivity while palpitations were not observed during beta-blockade. Asymptomatic hypoglycemia did not occur.