PIP: To investigate the possible changes in adrenocortical function during the use of different oral contraceptives, 43 women of fertile age were studied. 35 were using orgal contraceptives of the estrogen-gestagen type, the estrogen-gestagen sequential type, or the low-gestagen type. 8 women were controls. Each member of the test groups had been taking contraceptive pills for at least 2 menstrual cycles. Adrenocortical function was measured by assaying photofluorimetrically the 11-OHCS content of the plasma during the synthetic adrenocortioctrophic hormone (ACTH) (Homactid) test. The dose of the hormone used was 10 mcg given im. Plasma samples were obtained before and 15, 30, 60, and 120 minutes after injection. Tests were done on Days 15-20 of the menstrual cycles. The plasma 11-OCHS level in the low-gestagen group was the same as in controls both before and during the test. The combined type contraceptives had an elevating effect on the 11-OHCS level in the plasma; these levels both before and during the ACTH test ranged from nearly significant to p less than .01 with some of the readings reaching significance at the p less than .001. The difference is assumed to be due to an increased transcorting content of the plasma and to the increased biological half-life of cortisol induced by estrogen. This could also explain why the metabolic change noted in association with estrogen-gestagen oral contraceptives is similar to that seen in corticosteroid-induced diabetes. Similar readings were found for the patients taking the sequential contraceptives, with values ranging from nearly significant at 0-15 minutes to highly significant (p less than .001) from 30 to 120 minutes.