Epristeride is a novel selective and specific uncompetitive inhibitor of
steroid 5alpha reductase isoform II, which has been
shown to inhibit conversion of testosterone to dihydrotestosterone and to retard growth of Prostate. Epristeride was well absorbed following oral administration and kept a high concentration in prostate. Oral administration of epristeride reduced prostate size of both dog and rat very markedly. It might result from decrease of DHT and promoting apoptosis of prostate cells. Morphometric analysis showed smaller size of acinar lumen and lower height of prostate epithelial cells than that of normals. The rate of condensation of chromatin and appearance of apoptotic bodies in dog prostate was increased after treatment with epristeride. Further study found epristeride induced to downregulate protein expression of bcl-2 gene. Pharmacology and
toxicology studies suggested that epristeride had high selective effect on the prostate, while no significant effect on cardiovascular system and respiratory system. Reproductive toxicity study indicated that there was no effect on fertility and sperm motility. Mutagenicity tests showed that epristeride is not mutagenic.