Abstract
The in vitro assay (Saffran test) of corticotropin A against the present U.S.P. corticotropin standard (crude corticotropin) was in good agreement with the ascorbic acid depletion assay or Sayers test. The in vitro assay of corticotropin may thus be used instead of the Sayers test, when crude corticotropin and corticotropin A are either the standard or the sample in an assay. The in vitro assay of extracts of adenohypophyses of rats yielded about 10 times more corticotropin than the Sayers test, when compared with the present standard. Data from 130 in vitro assays showed parallelism of the dose-response curves of crude corticotropin and corticotropin A; the mean index of precision, gamma, was 0.16.