RELATIVE PRODUCTION OF FLUORESCENT AND UV-ABSORBING STEROIDS BY INCUBATED RAT ADRENAL GLANDS

Abstract

Silber's fluorometric method for corticosteroids was used concurrently with Saffran's UV-absorption method for Δ 4-3-keto-steroids to determine the relative production of fluorescent and UV-absorbing compounds by incubated rat adrenal glands, in the presence or absence of ACTH. The production of both types was markedly increased by ACTH. The F/UV ratio, close to unity after 15 minutes of incubation with or without ACTH, decreased to values of 0.51 for non-stimulated, and 0.62 for stimulated glands, after 2 hours. The similarity of these values with the red./UV ratios, observed by Elliott et al. under comparable conditions, suggests that the compounds determined by fluorometry correspond to the blue tetrazolium-reducing steroids with α-ketolic side chains, characterized by these investigators. The nature of these steroids, and of the UV-absorbing, non-reducing, non-fluorescent material is discussed in the light of chromatographic findings. Concurrent assays of rat pituitary extracts by the UV-absorption and fluorometric methods, in Saffran and Schally's adrenal incubation system, yielded comparable results.