THE IN VITRO BIOSYNTHESIS OF 18-HYDROXYCORTICOSTERONE-4-14C BY SLICES OF ZONA GLOMERULOSA OF BEEF ADRENALS AND BY HUMAN ADRENALS

Abstract

ABSTRACT The in vitro steroidogenesis of the zona glomerulosa of beef adrenals and that of human adrenals was investigated. Tissue slices were incubated in a Krebs-Ringer - bicarbonate medium containing 200 mg% of glucose with progesterone-4-14C and corticosterone-4-14C as precursors. After incubation the media were extracted exhaustively with chloroform and the dry residue of the solvent extract fractionated on paper chromatographic systems. The identity of one of the 14C transformation products produced from both precursors was investigated in detail. The substance absorbed ultraviolet light (λmaxEtOH: 241 mμ), but reduced alkaline blue tetrazolium only very slowly. The mobility of the unknown alone and diluted with inactive carrier was identical with that of the 20→ 18 cyclic hemiketal of 18-hydroxycorticosterone. The identity of the biosynthetic material with the closed form of 18-hydroxycorticosterone was established by isotopic dilution techniques and the formation of derivatives. It was observed that the compound can exist in at least three different tautomeric forms. The yield of 18-hydroxycorticosterone with beef zona glomerulosa was 3.8% from progesterone and 6.8% from corticosterone.