A PERIOD OF APPEARANCE OF NADH-DIAPHORASE ACTIVITY IN MITOTIC CYCLE OF EHRLICH'S ASCITES TUMOR CELLS

DDN male mice were injected with 250μc of thymidine-H3 intraperitonealiy 8 days after intraperitoneal inoculation of Ehrlich's ascites tumor cells. Samples of ascitic fluid were obtained 2, 5, 8, 11, 14, 17 and 20 hours respectively after a single injection of the labelled thymidine, and the tumor cells were collected. The interrelation of NADH-diaphorase activity and nuclear incorporation of the label was examined in the cells of each fluid.1. Of the cells showing NADH-diaphorase activity (about 10% of all the cells), the percentage of the cells showing nuclear incorporation of the label was about 36 two hours after injection, 78 after 5 hours, 90 after 8 hours, 92 after 11 hours, 87 after 14 hours, 64 after 17 hours and 35 after 20 hours.2. From the results of this and the previous reports, it was assumed that the NADH-diaphorase activity of Ehrlich's ascites tumor cells begins to appear in antephase, increasing progressively to the peak, and falls markedly in the latter prophase, almost disappearing after metaphase.3. The number of chromosomes of Ehrlich's ascites tumor cells used in this study was mostly 72 or 74, with the contamination of the cells of other numbers.