[In vitro studies on the antitumor effect of cis-diamminedichloroplatinum II (cisplatin) against ovarian adenocarcinoma cell line of the rat].

The survival of asynchronous rat ovarian adenocarcinoma cells (ROT68/C1) treated for 1 hr with more than 0.5 microgram/ml of cis-diamminedichloroplatinum (II) (Cisplatin) revealed a marked decrease in a dose-dependent manner, as estimated by the vitro colonyforming method. Although the ROT68/C1 cells showed no significant sensitivity to 0.1 microgram/ml of Cisplatin for 1 hr, more than 50% of the cells were killed when the exposure interval was prolonged for 16 hr. The decrease in percent survival of cells with increasing Cisplatin concentration was parallel to that of the uptake of 3H-thymidine, whereas the uptake of 3H-uridine was not inhibited in a dose-dependent manner. The DNA histogram pattern of nontreated asynchronous ROT68/C1 cells was distributed widely and a peak of accumulation was observed near 6C. When the cells were exposed to more than 0.5 microgram/ml of Cisplatin for 1 hr, the accumulation of cells near 2C was observed to occur more rapidly with increasing concentration. The cells distributed near 2C appeared to be cells with karyorrhexis and damaged irreversibly.