Effects of two structurally different antispermatogenic compounds on the synthesis of steroids in rat testes.

The influence of two drugs with antispermatogenic properties on steroid biosynthesis has been studied in rat testes in vitro with pregnenolone as the substrate. 20-438, an indenopyridine derivative increased the relative conversion of pregnenolone to progestins and estradiol, whilst decreasing the conversion of substrate to testosterone and androstenedione. PMHI, a pipecolinoindane derivative, reduced testosterone levels in the testes without altering the relative conversion of pregnenolone to various steroids. This suggests that the agent is partially inhibiting the biosynthesis of androgen precursors leading to a testosterone deficiency in testicular tissue which may result in reduced spermatogenesis.