[5 alpha-reductase and prostate]

The human prostate is a complex organ composed of four glandular zones that differ in their histology and biology. In addition to this anatomical organization, the prostate is mainly composed of epithelial and mesenchymal tissues. Two pathologies affect the growth of the prostate: cancer and benign prostatic hyperplasia. Anatomical and pathological studies have shown that stromal enlargement is the first step in the process of BPH and that both transition and periurethral regions are the exclusive sites of origin. Because the first step of androgen action is the reduction of testosterone into dihydrotestosterone by the 5 alpha-reductase, it have been postulated that modification of this enzymatic activity may play an important role in BPH development. However DHT production alone cannot explain the hyperplastic development of the gland. Thus it has also been postulated that androgen-growth factor interaction may be an important feature of this growth: these growth factors include the IGF axis. An interaction between androgen pathway and sympathethic system, via alpha-adrenoreceptor may also be suspected.