Quantification of endogenous testosterone, 5α-dihydrotestosterone and 5α-androstane-3α, 17β-diol in subcellular fractions of the prostate, bulbocavernosus/levator ani muscle, skeletal muscle and heart muscle of the rat

Abstract

Testosterone (T), 5α-androstan-17β-ol-3-one (dihydrotestosterone, DHT) and 5α-androstane-3α,17β-diol (3α-diol) were measured by radioimmunoassay (RIA) in the tissue homogenates, cytosols and nuclear fractions of the prostate (PR), bulbocavernosus/levator ani muscle (BCLA), skeletal muscle (musculus quadriceps femoris, SM) and heart muscle (HM) of adult male rats. The main results were: (a) In all three of the PR preparations the main metabolite found was DHT. T could not be detected in the cytosol and 3α-diol was absent in the nuclei, (b) The muscles contained predominantly T. Besides the homogenates DHT was found only in the nuclear fractions. 3α-diol could only be detected in the homogenates and HM-cytosol but not in the nuclei, (c) Comparing the various organs, a clear ranking, PR > BCLA > SM > HM, was found for DHT in the homogenates and similarly but less pronounced in the nuclear fractions, whereas T was generally higher in the muscle homogenates, cytosols and nuclear fractions than in the PR. These data are discussed with respect to the present knowledge of specific androgen accumulation and metabolism in the different organs.