The uptake of tritiated thymidine by newly transplanted ehrlich ascites tumor cells

Abstract

When large numbers of Ehrlich ascites tumor cells were transplanted into the peritoneal cavity of mice, they were found capable of taking up tritiated thymidine within one minute after transplantation. There were only a few necrotic cells after transfer, and the percentage of cells labeled by tritiated thymidine remained constant up to 30 hr after inoculation. These findings indicated that cell death was negligible and that Ehrlich cells transplanted into new hosts continued to synthesize DNA without an appreciable lag. A temporary depression of the mitotic index and a slight delay in the appearance of labeled mitoses suggested a lengthening of that phase of the cell cycle immediately preceding mitosis. However, the length of the DNA synthesis phase did not differ from the values found in previous experiments with tumors in various stages of growth. The percentage of Ehrlich ascites tumor cells labeled by a single injection of tritiated thymidine decreased after the first few days of tumor growth, but it promptly increased again when these cells from tumors in advanced stages of growth were transplanted into new hosts.