The effect of intravenously-administered ACTH on plasma 17,21-dihydroxy-20-ketosteroids in normal individuals and in patients with disorders of the adrenal cortex.

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-hydroxycorticosteroids 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-20ketosteroids in plasma (4, 5), more direct measurement of adrenal activity has become possible. Recent investigations have demonstrated the usefulness of the plasma 17-hydroxycorticosteroid response to ACTH in assessing adrenal function in normal individuals and in certain adrenocortical disorders (6-11). Studies have been performed in this laboratory on plasma 17-hydroxycorticosteroid levels in patients 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 hypopituitarism, in which plasma 17-hydroxycorticosteroid levels determined before and after ACTH administration may give a more accurate picture of adrenal capacity than single plasma 17hydroxycorticosteroid levels. These findings prompted an evaluation of plasma 17-hydroxycorticosteroid response to ACTH in patients with a variety of disorders of the adrenal cortex as compared with normal subjects.