Development of a quantitative RT-PCR method to study 5alpha-reductase mRNA isozymes in rat prostate in different androgen status.

Abstract

The incidence of prostate cancer (PCa) and benign prostatic hypertrophy (BPH) continues to rise in the Western world. The development and growth of the prostate gland depends on androgen stimulation. Dihydrotestosterone (DHT) is the primary androgen responsible for prostate development and also for the pathogenesis of benign prostatic hyperplasia (BPH). DHT is synthesized in prostate from circulating testosterone (T) through the action of 5alpha-Reductase (5alpha-R) (EC 1.3.99.5), which occurs as two isozymes, type-1 and type-2. Both types are expressed in the prostate: type-2 isozyme is predominantly expressed in prostate and is implicated in BPH and PCa; type-1 isozyme is also increased in some prostatic adenocarcinomas. In recent years, various inhibitors of type-2 isozyme or of both type-1 and type-2 isozyme have been used in prostatic diseases. We present the first published measurements of mRNA levels of steroid 5alpha-R isozymes in the ventral prostate of rats of different androgen status. We used a novel method that combines the high specificity of competitive PCR with the sensitivity of laser-induced capillary electrophoresis (LIF-CE). We demonstrated that T and DHT androgens control the expression of both 5alpha-R isozymes in rat prostrate. This approach could be of great value for the study of prostate diseases in humans and would allow study at the transcriptional level of the effects of drugs that inhibit either or both of these isozymes.