INDIVIDUALS AND IN PATIENTS WITH DISORDERS OF THE ADRENAL CORTEX 1

The response of the adrenal cortex to exogenous ACTH has been recognized as one of the more specific and quantitative tests of adrenal function (1). Changes in the 24-hour excretion values of urinary 17-ketosteroids and 17-hydroxycorticos-teroids during ACTH administration have proved to be valuable indices of adrenocortical capacity (2, 3). With the development of technics for the chemical estimation of free 17, 21-dihydroxy-20-ketosteroids in plasma (4, 5), more direct meas-urement of adrenal activity has become possible. Recent investigations have demonstrated the use-fulness of the plasma 17-hydroxycorticosteroid response to ACTH in assessing adrenal function in normal individuals and in certain adrenocorti-cal disorders (6-11). Studies have been performed in this laboratory on plasma 17-hydroxycorticosteroid levels in pa-tients with endocrine and non-endocrine diseases (12). During the course of these investigations, it became apparent that there are disease states, particularly primary adrenal insufficiency and hy-popituitarism, in which plasma 17-hydroxycorti-costeroid levels determined before and after ACTH administration may give a more accurate picture of adrenal capacity than single plasma 17-hydroxycorticosteroid levels. These findings prompted an evaluation of plasma 17-hydroxy-corticosteroid response to ACTH in patients with a variety of disorders of the adrenal cortex as compared with normal subjects