LY191704: A Selective, Nonsteroidal Inhibitor of Human Steroid 5 Alpha-Reductase Type 1

In 1993, LY191704 was characterized as a selective and potent inhibitor of the human steroid 5 alpha-reductase type 1 enzyme, which is involved in converting testosterone to dihydrotestosterone (DHT). The compound showed an IC50 of approximately 10 nM in a human genital skin fibroblast cell line and 12 nM in cultured human prostate cells from BPH patients, but it did not inhibit the enzyme in freshly isolated prostate cells. LY191704 demonstrated around 5000-fold selectivity for type 1 over type 2 isozyme and was a noncompetitive inhibitor with an apparent Ki value of 4.0 nM. The study suggested that LY191704 could be useful for treating conditions like prostatic hyperplasia and potentially androgenic alopecia, as type 1 isozyme is predominant in the scalp. The document implies that a combination of LY191704 with a type 2 inhibitor could be a therapeutic strategy for these conditions. The number of people or the exact sample size involved in the study was not provided.