Cytochemical properties of human endometrial cells in vitro

The cytochemical properties of the human endometrial cell nuclei have been studied during the menstrual cycle in eight women by means of two different microfluorometric methods, both considered to be specific for DNA: the BAO-Feulgen method and a method based upon an interaction between DNA and mithramycin. An in vitro system was developed where dissociated endometrial cells were studied at 4 hours and 18 hours of incubation at 37 degrees C. The cytochemical properties of the dissociated endometrial cells did not change significantly in the in vitro system used. An increase in the BAO-fluorescence intensity per cell nucleus was observed in all the endometrial samples when compared with the diploid standard DNA value of a non-growing cell population. A similar increase in the mithramycin fluorescence intensity per cell nucleus appeared only during the secretory phase. It is suggested that the nucleoproteins play an essential role in changing the cytochemical properties of the human endometrial cell nuclei during the menstrual cycle.