Effects of Metyrapone and a Combined α- and β-Adrenergic Blockade on Plasma Glucose Recovery from Insulin-Induced Hypoglycaemia in Pigs

Summary

The recovery of plasma glucose from insulin-induced hypoglycaemia was investigated in growing pigs during an inhibition of corticosteroid secretion (metyrapone infusion), an α- and β-adrenergic blockade (phentolamine and propranolol infusion) or a combination of both treatments. In pigs which received an infusion of metyrapone for 4 h before and 3 h after a bolus injection of insulin (0.1 IU/kg body-weight), the plasma glucose response did not differ significantly from control animals. The infusion of phentolamine and propranolol (in each case 120 μg/kg/h for 3 h after a priming dose of 100 μg/kg) starting at the time of insulin injection significantly attenuated the restoration of normoglycaemia. An additional infusion of metyrapone increased this effect significantly only at the end of the experiment. The results indicate that adrenergic mechanisms are involved in the glucose counterregulation after an insulin-induced hypoglycaemia in pigs and the glucocorticoid secretion may become critical when the catecholamine response is impaired.

Key words

Insulin administration - Glucose - Phentolamine - Propranolol - Metyrapone