EFFECTS OF ANGIOTENSIN-II ON PROLIFERATION OF ESTROGEN-INDUCED RAT PITUITARY-TUMOR AND HUMAN PROLACTINOMA CELLS IN-VITRO

The effects of different concentrations of angiotensin II (At II) on t he proliferation of diethylstilboestrol-induced rat pituitary tumor an d human prolactinoma cells were studied in vitro. The incorporation of [H-3]thymidine into DNA of tumor cells was used as a? index of prolif eration. It was found that At II stimulated the incorporation of triti ated thymidine into rat pituitary tumor cells. The dose-response curve was bell-shaped with the maximal effect at 10(-10)M. The effect of At II was abolished by an At II antagonist, saralasin. Similar results w ere obtained when the effect of At II on the primary culture of human prolactinoma cells were studied. These findings, taken together with o ther observations, suggest a role of At II in the control of the pitui tary cell proliferation.