AN IN VITRO ASSAY OF CORTICOTROPHIN

Abstract
The ability of corticotropin to increase the corticoid output of rat adrenals in an isolated gland system has been developed as a useful assay method for the measurement of corticotropin potency. The extra corticoids produced by stimulation are measured in terms of cortisone. Log dose response curves are presented for corticotropin levels from 0.002 to 0.135 I.U/100 mg adrenals. A 4 point assay design, the precision of corticoid measurements, and the characteristics of the log dose response curves for a number of types of corticotropin are given. With 4 measurements of each dose level the average lambda s/b for 20 assays was 0.209 [plus or minus] 0.085 (S.D.).