Previous studies on prostate blood flow regulation have indicated that androgen regulates prostate blood flow. However, the mechanism responsible for this regulation is unknown. In the present study, we focused on the effects of vascular endothelial growth factor (VEGF), a key factor responsible for angiogenesis and androgenic blood flow regulation. We examined in vivo the effect of VEGF on prostate blood flow and its participation in the androgenic regulation of this blood flow using a castrated rat model following sub-capsular intra-prostatic injection method. We found that VEGF is involved in blood flow regulation with an activity equal to that of dihydrotestosterone (DHT). The effect of VEGF on prostate blood flow was already seen at 30 min after the administration. The elevating effect of DHT on castrated rat prostate blood flow was abolished by co-administration of DHT with neutralizing anti-VEGF antibody. The change in VEGF-A mRNA expression in response to androgen stimulation was examined by double fluorescent probe quantitative PCR (Taqman PCR). The results showed that androgenic regulation of VEGF gene expression occurred shortly after androgen stimulation. VEGF gene up-regulation was abolished or down regulated by co-administration of neutralizing anti-VEGF antibody.

This is the first report on the importance of VEGF in the androgenic regulation signaling pathway which affects prostate blood flow. Alternative treatment targeted toward anti-VEGF activity as a substitute for ordinary anti-androgenic therapy may be effective against prostate diseases, especially those with androgen-independent and hyper-hemorrhagic status.