Yohimbine hydrochloride inhibits benign prostatic hyperplasia by downregulating steroid 5α-reductase type 2

Benign prostatic hyperplasia (BPH) is a frequently encountered disease in older men that affects sexual function and is capable of causing lower urinary tract dysfunction. Unfortunately, current treatment options for BPH primarily seek to address the lower urinary tract dysfunction aspect of the disease and do not improve sexual function. Yohimbine has been effectively used for decades to treat erectile dysfunction. Therefore, the objective of this study was to evaluate the inhibitory effect of yohimbine on BPH and explore the associated underlying mechanisms. Thirty-six rats were randomly divided into the control, BPH, finasteride (1 mg/kg), and yohimbine (2, 4, and 8 mg/kg) groups. Except for the rats in the control group, those in the other groups were subcutaneously injected testosterone propionate (5 mg/kg/day) daily for a period of 4 weeks to establish BPH models. They were also administration the corresponding drug daily for a period of 6 weeks. After the treatments, in addition to determining prostate wet weight and index, the histopathological status of the prostate was observed, and the levels of testosterone, dihydrotestosterone, prostatic acid phosphatase, the prostate-specific antigen, proliferating cell nuclear antigen, and steroid 5α-reductase were determined. Specifically, the administration of 2, 4, and 8 mg/kg yohimbine inhibited prostatic index increase by 46.7, 55.1, and 69.3%, respectively, in BHP rats. Further, yohimbine significantly reduced the levels of dihydrotestosterone, prostatic acid phosphatase, prostate-specific antigen, proliferating cell nuclear antigen, and steroid 5α-reductase, suggesting that it exerts beneficial effects against BPH by modulating the steroid 5α-reductase pathway.