| Abstract: | Pituitary cells from hamsters bearing diethylstilbestrol induced renal adenocarcinomas were cultured in vitro. Dispersed cells in plastic dishes were viable for up to two weeks in Dulbecco's modified Eagle's medium supplemented with 17.5% of 6:1 horse serum to fetal calf serum. The secretion of alpha-melanocyte stimulating hormone and prolactin into the medium were measured by radioimmunoassay. The concentrations of both were elevated by day 3 in the medium from the hyperplastic pituitaries obtained from the estrogen treated, tumor bearing hamsters. Neither DES (10(-8)M) nor tamoxifen (10(-7)M) influenced the secretion of either hormone and neither altered either cell number or DNA synthetic activity as measured by thymidine incorporation. The secretion of hormones and the growth of the pituitary cells were, however, decreased by charcoal treatment of the serum. The results suggest that the elevation of serum alpha-MSH and prolactin observed in DES implanted hamsters is due to pituitary secretion of the hormones but that DES probably does not act directly on the pituitary to control the secretion. |
