Morphologic and enzyme-cytochemical changes in uterine adenocarcinoma cells of a rat by direct application of progesterone in vitro

HTP/C1/P8 culture, a subclonal cell line of HTP/C1 culture derived from a rat uterine adenocarcinoma, has been subcultivated in a culture medium containing progesterone, 8 μg/ml. HTP/C1/P8 cells revealed a more differentiated form by light and electron microscopy, compared with original HTP/C1 cells growing in a culture medium without progesterone. The effect of progesterone on these uterine adenocarcinoma cells seemed to be direct, as evidenced by the significantly higher uptake of ³H]progesterone into the cells in vitro. Enzyme-cytochemical changes of the cells by the direct application of progesterone is discussed in relation to the morphologic differentiation of these cells.