Hyperglucagonism Induced by Glucocorticoid Treatment in Man

To elucidate further the nature of glucocorticoid-induced alteration of carbohydrate metabolism, plasma glucagon levels, both basal and after an arginine stimulus, were studied in normal volunteers before and after glucocorticoid treatment. In one group of 13, after oral administration of prednisolone (40 mg daily, for four days) an increase in fasting glucagon levels (+ 24 pg per milliliter) and a glucagon hyper-response to a high arginine load (+ 133 pg per milliliter at 10 minutes, + 80 pg per milliliter at 20 minutes and + 51 pg per milliliter at 30 minutes) were accompanied by an elevation of glucose, amino nitrogen and insulin concentrations. In another group of eight, after oral administration of prednisolone (60 mg daily for three days) a rise in fasting glucagon levels (+ 17 pg per milliliter) and a greater glucagon response to a low arginine load (+ 68 pg per milliliter at 10 minutes) were observed. In a third group of five, the intravenous injection of prednisolone (100 mg) failed to alter plasma glucagon values, thus suggesting that its effect on the alpha cell is not direct. Glucocorticoid-induced hyperglucagonemia could represent another way in which these hormones exert their diabetogenic effect.