Effect of osaterone acetate administration on prostatic regression rate, peripheral blood hormone levels and semen quality in dogs with benign prostatic hypertrophy

The effects of osaterone acetate (OSA), which is an anti-androgen agent bei ng developed as a therapeutic drug for benign prostatic hypertrophy (BPH) i n dogs, on the degree of prostatic regression and semen qualities were inve stigated. Prostatic regression was compared between dogs with and without o rchidectomy. Five male beagles aged 5-9 years were used in the experiment. OSA was orally administered at doses; of 0.2 mg/kg and 0.5 mg/kg for one we ek. The prostatic regression rate one week after the end of administration was 62.6% on average. In the orchidectomized group, the mean regression rat e one week after orchidectomy was 60.1%. However. the prostate became enlar ged 6 months after administration, compared to the size prior to administra tion. The above Endings suggested that OSA is clinically applicable as a th erapeutic drug for BPH in dogs, and inhibits prostatic hypertrophy during t he early phase.