Effects of estrogens and progestogens on the membrane permeability and growth of human prostatic carcinoma cells (PC-3) in vitro.

The effects of estrogens and progestogens in the management of prostatic adenocarcinoma are generally believed to be related to their suppressive effect on the hypothalamic-pituitary-testicular axis, but other mechanisms have also been suggested. The present study was designed to investigate if an androgen-insensitive human prostatic cancer cell line (PC-3) is sensitive to estrogens or progestogens and to elucidate possible mechanisms of action. Both estrogens and progestogens in high doses (10(-5) M) suppressed tumor cell growth. At these high doses medroxyprogesterone acetate (MPA) most effectively reduced the uptake of 86rubidium chloride, indicating the strongest effect on ion transport and membrane permeability. Effects on rubidium transport were also seen after estrogen treatment. It is suggested that estrogens and progestogens have direct cytotoxic effects on prostatic carcinoma cells in vitro, possibly by an effect on the cell membrane.