Early adrenal hypofunction in patients with organ-specific autoantibodies and no clinical adrenal insufficiency.

Idiopathic Addison's disease occurs frequently in association with other organ-specific autoimmune diseases, and autoantibodies to adrenal cortex are markers of this condition. A variable asymptomatic period with subtle adrenal dysfunction may precede the onset of clinical manifestations. We studied the pituitary-adrenal axis by measuring plasma ACTH, cortisol, and 17 alpha-hydroxyprogesterone after ovine CRH (100 mu g as an iv bolus) stimulation in 19 patients with organ-specific autoimmune disease and adrenal autoantibodies, in whom adrenal steroids were normal under baseline conditions and normally responsive to a standard ACTH stimulation test (250 mu g). In all subjects, oCRH produced a normal increase in plasma ACTH. Plasma cortisol, which was normoresponsive in 11 subjects, showed little or no increase in 8 subjects. Two of these patients developed overt adrenal failure after 1 yr. The 17 alpha-hydroxyprogesterone response to oCRH, tested in 10 of 19 patients, paralleled that of plasma cortisol, excluding a steroidogenic block at the 21-hydroxylase site. Our data demonstrate the existence of a very early phase of Addison's disease in which adrenal function shows an impaired response to ovine CRH-stimulated ACTH.