Effect of prolactin on the population of epithelial cells from ventral prostate of intact and cyproterone acetate-treated peripubertal rats: stereological and immunohistochemical study.

The interactions between steroid and nonsteroid hormones in the prostate are of special interest during the growth phase of the gland. The purpose of this work is to study the influence of prolactin (PL), with or without androgenic blockade, on epithelial cells from peripubertal rat ventral prostate. Twenty male peripubertal Sprague-Dawley rats were grouped as controls, or treated with cyproterone acetate (CA), CA plus PL (CA-PL), or PL. The total number (N total) of epithelial cells, and their labeling indices to proliferative cell nuclear antigen (LI PCNA), apoptosis (LI apoptosis) and androgen receptors (LI AR) were measured. CA and PL treatment significantly decrease the N total, but the LI PCNA was unchanged. We have observed a greater LI apoptosis in pharmacologically castrated animals without PL than in the rats with androgenic blockade with PL. The LI AR does not change with CA treatment in the ventral region, but the PL significantly increases it. Androgenic blockade and PL decrease the number of epithelial cells from the ventral prostate. These changes are not attributable to the decrease of cell proliferation, rather to the increase of epithelial apoptosis. The increase of cells expressing AR after treatment with PL might be attributed to the decrease of testosterone secretion caused by the hyperprolactinemia. PL does not modulate the size of the ventral prostate in prepubertal rats.