CONCENTRATIONS OF ANDROGENS IN NUCLEI OF SEMINIFEROUS TUBULES IN DEVELOPING AND MATURE RATS

Homogenates of seminiferous tubules obtained from 26-, 32- and 60-day-old rats were fractionated by ultracentrifugation and the concentrations of testosterone, dihydrotestosterone and 5α-androstane-3α,17β-diol were determined by radioimmunoassay in unpurified subcellular fractions and purifed nuclei. The three androgens were detected in cytosol at all ages. Similar to what has been described for whole tissue homogenates, testosterone was the main steroid present in the cytosol of mature rats while reduced androgens were predominant in young animals. 5α-androstane-3α,17β-diol was present in high concentrations in the cytosol fraction of 26-day-old rats but was undetectable in nuclei at all ages. In the nuclei of young rats the levels of androgens were higher than in 60-day-old rats, particularly the concentrations of dihydrotestosterone. The absence of 5α-androstan-3α,17β-diol in nuclei suggests that this steroid does not stimulate transcription in this tissue. © 1979.