COMPARISON BETWEEN β1–24CORTICOTROPHIN DW-75 (SANDOZ) AND NATURAL CORTICOTROPHIN IN NORMAL ADULTS PRETREATED WITH DEXAMETHASONE

Three different ACTH preparations, a synthetic pentacosapeptide (DW-75, Sandoz), a synthetic tetracosapeptide (Synacthen®) and natural ACTH (Acton®) were administered to 11 normal young experimental subjects by intravenous injection. The biological activity was measured by the rise in plasma 11-OH-corticosteroids in the experimental subjects in whom the endogenous ACTH production was suppressed by means of dexamethasone.The study of the stimulating effect on the adrenal cortex showed that both with regard to magnitude of the maximal response and the duration of the response, the three preparations had more or less the same activity per international unit as measured by Sayers' subcutaneous test. In addition, it was found with all three ACTH preparations that the intravenous injection of a dose between 1 IU and 2 IU gave a maximal rise in plasma 11-OH-corticosteroids.