The antigonadotropic action of testosterone but not 7alpha-methyl-19-nortestosterone is attenuated through the 5alpha-reductase pathway in the castrated male rat pituitary gland.

The enzyme 5alpha-reductase plays a significant role in the prostate to amplify the action of testosterone (T) by converting it to a more potent androgen, dihydrotestosterone (DHT). The role of 5alpha-reductase in the testosterone feedback inhibition of gonadotropin secretion from the pituitary has not been elucidated. Therefore, we investigated the role of 5alpha-reductase on T action in in vitro…