Apparent Discrepancies in Evaluation of Adrenocorticotrophic Hormone (ACTH) Activity by Two Assay Methods

Abstract

Evidence is presented from parallel assays of 5 ACTH prepns., by the ascorbic acid-depletion method and by the adrenal wt. maintenance test in hypophysectomized rats, that the results of those two tests do not give directly correlative activity measurements. The evidence suggests that assessment of potency may vary according to the assay technique employed. The suggestion is advanced that ACTH prepns. be assayed routinely by more than one method. Possible explanations are advanced to explain the difference in activity of ACTH prepns. subjected to the various chemical and physical procedures employed in these expts., viz., pepsin digestion, acid hydrolysis, and treatment with heat in the boiling water bath.