Effects of 17beta-estradiol and progesterone on growth and morphology of human endometrial carcinoma cells in vitro.

The effects of 17beta-estradiol and progesterone on the rate of growth and the morphological changes of human endometrial adenocarcinoma cells were studied in in vitro culture. 17beta-Estradiol enhanced their growth and produced no cellular morphological changes at low concentrations of less than 1 microgram/ml, whereas it suppressed their growth and produced such cellular changes as enlargement of nuclei, karyorrhexis, and karyolysis at high concentrations of more than 5 microgram/ml. On the other hand, progesterone did not affect the cells at less than 1 microgram/ml, but it suppressed their growth and induced differentiation at more than 5 microgram/ml. Specific morphological changes produced by progesterone were characterized by multinucleation, multinucleolation, prominent Golgi apparatus, occurrence of vacuoles, and papillary-like arrangement of cells. These features suggested that progesterone acted directly on the endometrial carcinoma cells and induced their histological differentiation. These changes could not be detected by the adminstration of 17beta-estradiol.