The effect of prolactin on human BPH epithelial cell proliferation

Epithelial cell monolayers derived from specimens of human benign prostatic hyperplasia (BPH) tissue by an explant culture technique were cultured with prolactin in the presence and absence of androgens. Proliferation of the cells was measured by both autoradiographic assessment of [3H]-thymidine uptake and stathmokinetic procedures. Prolactin significantly stimulated the growth of these cells in the concentration range 0.5 mIU/ml to 10 mIU/ml but was inhibitory at a concentration of 100 mIU/ml. In the presence of testosterone (1 X 10(-7) M), prolactin at low concentrations (greater than 1 mIU/ml) but not at 10 mIU/ml, the concentration at which all other experiments were performed, produced a further stimulation in the proliferation. The increase in growth seen with cells cultured with 5 alpha-dihydrotestosterone (1 X 10(-7) M) was reduced with addition of prolactin at high concentrations (10-100 mIU). When the fetal calf serum used in the cultures was stripped of endogenous steroids, prolactin still increased cell proliferation, although to a reduced extent. This indicated that the effects of prolactin were not dependent on the presence of androgens.