Steroidogenic responses to varying parenteral routes of administered (alpha 1-18) ACTH

In healthy human subjects, the steroidogenic responses to a single injection of alpha 1-18 ACTH by the subcutaneous, intramuscular, and intravenous (IV) routes were assessed by measurement of plasma cortisol levels, 17-hydroxycorticosteroid excretion, and cortisol secretion rates. Results showed that regardless of the parenteral route used, alpha 1-18 ACTH at doses of 1.0 and 0.5 mg was an effective adrenocorticotropic agent; however, with the IV route, the effect was considerably prolonged. The patterns of disappearance within the plasma of alpha 1-18 ACTH and alpha 1-24 ACTH were compared following a single IV injection of these compounds labeled with 125I. ALPHa 1-18 acth produced only a slight initial rise and a slower decline in plasma radioactivity compared to alpha 1-24 ACTH, suggesting slower degradation of alpha 1-18 ACTH. Administered as a single IV injection, alpha 1-18 ACTH has a prolonged effect on steroidogenesis and has potential for being a useful diagnostic and therapeutic ACTH preparation.