Abstract
In a 28-yr-old woman with idiopathic hypoparathyroidism, the insulin and glucagon responses to an oral glucose tolerance test (O-GTT), intravenous glucose tolerance test (IV-GTT) and arginine tolerance test (ATT) were studied before (serum calcium concentration: 3.4 mEq/l) and after treatment (serum calcium concentration: 4.6 mEq/l).
In the case of O-GTT, impaired glucose tolerance was apparent before treatment, but a normal blood sugar response and improved insulin secretion were observed after treatment. In IV-GTT, the blood glucose and insulin responses were similar before and after treatment. Glucagon suppression in O-GTT and IV-GTT revealed a similar pattern before and after treatment. In ATT, decreased insulin release and increased glucagon secretion were observed before treatment, but they were normalized after treatment.
These results suggest that insulin releases to glucose and arginine are dependent on the serum calcium concentration, but glucagon secretion may be independent of serum calcium concentration in idiopathic hypoparathyroidism.
