Equine 5α-Reductase Activity and Expression in Epididymis

The study investigated 5α-reductase activity and expression in the epididymis of stallions, focusing on the conversion of progesterone and testosterone to DHP and DHT. It found that the type 1 isoform of 5α-reductase predominated in the equine epididymis, while the type 2 isoform was not detected. Both finasteride and dutasteride effectively inhibited 5α-reductase activity. The study also explored pregnenolone as a potential substrate but found no evidence supporting its direct metabolism by equine 5α-reductases. This research provided insights into the enzymatic processes in the equine epididymis, contributing to the understanding of steroid metabolism in horses.