The periurethral zone of the prostate of the cynomolgus monkey is the most sensitive prostate part for an estrogenic stimulus

In man, benign prostatic hyperplasia (BPH) develops in the so-called transition zone of the periurethral region of the prostate. Assuming that estrogens have a specific effect in this context, it would be expected that the periurethral glands are the most sensitive prostate part for an estrogenic stimulus. Morphological and immunocytochemical studies of serial sections of the prostate of castrated male adult cynomolgus monkeys treated with 17 beta-estradiol for a period of three months revealed stromal proliferation, hyperplasia, and hypertrophy of the keratin-positive basal cells and squamous epithelial metaplasia. These estrogen-induced effects were most marked or found exclusively in the dorsal periurethral glands--a finding that is inconsistent with pertinent animal studies conducted thus far on this subject, and which further bears out the suitability of the cynomolgus monkey as a model for investigating BPH.