[The metabolism of testosterone in the central nervous system (1). Analysis of testosterone metabolites in the anterior pituitary and hypothalamus using gas chromatography-mass spectrometry (GC-MS), and subcellular localization of testosterone converting enzyme].

The aim of this study was to identify accurately the structure of testosterone metabolites in the anterior pituitary and hypothalamus for the investigation of the mechanism of androgen action in the central nervous system. Tissue homogenate and cellular fraction of male rat anterior pituitary and hypothalamus were incubated with testosterone-4-14C and testosterone-19-CD3 (14C/D3 = 1) in the presence of NADH and NADPH. The incubation media were extracted, and they were separated using thin layer chromatography (TLC). Using autoradiogram of TLC, four main radioactive fractions were found on the TLC. The TFA or TMS derivatives of every fraction were analyzed using GC-MS. The main metabolites in the anterior pituitary were identified as 5 alpha-androstan-17-ol 3-one; androst-4-ene-3, 17-dione, 5 alpha-androstane-3 alpha, 17 beta-diol, 5 alpha-androstane-3 beta, 17 beta-diol, androst-4-ene-3 alpha, 17 beta-diol and androst-4-ene-3 beta, 17 beta-diol. The result in the hypothalamus was the same as that in the pituitary. The subcellular localization of metabolites in the anterior pituitary was as follows: 5 alpha-androstan-17-ol-3-one, 5 alpha-androstane-3 alpha, 17 beta-diol and 5 alpha-androstane-3 beta, 17 beta-diol were found in microsome; 5 alpha-androstane-3 alpha, 17 beta-diol and androst-4-ene-3 alpha, 17 beta-diol were found in soluble fraction. The result in the hypothalamus was the same as that in the pituitary.