PLASMA-CORTISOL RESPONSES AFTER INTRAMUSCULAR CORTICOTROPIN-1-24 IN HEALTHY-MEN

Intravenous infusion of corticotropin 1-24 (ACTH 1-24) followed by a p lasma cortisol measurement after 60 minutes of less than 20 mu g/dL in dicates clinically important glucocorticoid deficiency. In this study, we evaluated the morning plasma cortisol response to an intramuscular (IM) injection of ACTH 1-24 (250 mu g) in 64 healthy men. Plasma cort isol increased significantly 30 and 60 minutes after IM ACTH 1-24 (P < .0001). In most subjects, a maximal response was obtained at 60 minut es. The cortisol response correlated positively with the morning basal cortisol concentration. The lowest cortisol peak and the lowest incre ment observed after IM ACTH 1-24 were, respectively, 12.6 and 3.5 mu g /dL after 30 minutes and 16.3 and 5.3 mu g/dL after 60 minutes. We con clude that a plasma cortisol level less than 16.0 mu g/dL 60 minutes a fter IM ACTH 1-24 can be used as an index of glucocorticoid deficiency . Copyright (C) 1998 by W.B. Saunders Company.