Plasma alpha-cell glucagon in primary hyperparathyroidism.

Plasma glucose, insulin, and alpha-cell glucagon profiles were examined in ten adults with uncomplicated primary hyperparathyroidism before and 8-12 week after surgical removal of a single parathyroid adenoma. Treatment restored abnormal serum calcium and phosphorus concentrations to a normal range and reduced serum parathyroid hormone levels from 47 +/- 4 to 16 +/- 4 mu 1 Eq/ml (normal = 0-40). Plasma glucose curves during 100-g oral glucose tolerance, 30 min intravenous glucose (1.5 g/min), or arginine infusions (1.0 g/min) did not differ before and after surgery. However, basal and peak insulin concentrations were higher before treatment during these tests (p less than 0.05). Basal glucagon levels were unaffected by hyperparathyroidism (72 +/- 7 versus 77 +/- 7 pg/ml). Peak 30 min values after arginine provocation were also similar before and after treatment as was maximal suppression of basal glucagon during glucose infusions. Four patients also received 400 g lean beef meals. Glucose and glucagon responses over 240-min periods were nearly identical before and after surgery despite higher insulin levels before treatment. It is concluded that elevated serum parathyroid hormone and plasma insulin concentrations in primary hyperparathyroidism do not relate to abnormalities of plasma alpha-cell glucagon in the basal state or after glucose, arginine, or protein administration.