Subcellular localization of the C 19 -steroid reductase activities of female rat liver

The role of DPNH and TPNH in the reduction of [4- 14 C]-testosterone or [4- 14 C] and rostenedione by female rat liver homogenate and its subcellular fractions was studied. The extracted metabolites were separated by thin layer and paper chromatography. 5α-Androstane-3α, 17β-diol was the major metabolite. Androsterone and 5α-dihydrotestosterone occurred in lesser quantities and 5α-androstane-3β, 17β-diol, 5α-androstanedione and epiandrosterone in small amounts. Androstenedione (or testosterone) was produced only in the presence of DPNH. The omission of the coenzymes or TPNH-generating system resulted in only a trace amount of the metabolites.