The Effect of Finasteride on the Male Rat Brain

The study investigated the impact of finasteride, a 5-alpha reductase type 2 inhibitor, on the male rat brain, particularly focusing on psychosexual activity. It involved 24 fourteen-week-old male rats divided into three groups: a control group, a finasteride-treated group, and a finasteride withdrawal group. The finasteride-treated group received the drug for 4 weeks, after which they were sacrificed, while the withdrawal group was sacrificed 4 weeks after discontinuing the drug. The study found that dihydrotestosterone levels and the dihydrotestosterone to testosterone ratio decreased with finasteride treatment but returned to normal after discontinuation. Although 5-alpha reductase type 2 remained downregulated after drug withdrawal, the mRNA expression of 5AR and c-Fos did not significantly change but showed a tendency to increase during treatment. The conclusion is that finasteride affects the brain, including the hippocampus and VMPOA, by inhibiting 5AR-2 and reducing c-Fos protein activation, but these effects may reverse after stopping the drug for a long term.