Effects of Chloramphenicol on Incorporation of Glycine-2-C 14 into Mammalian Tumor Cell Proteins and Purines. ∗

Summary

The effects of 2 of the isomers of chloramphenicol, one the antibiotic, the other inactive toward bacteria, were tested on 2 in vitro systems consisting of mouse ascites tumor cells. In Ehrlich carcinoma cells the antibiotic isomer inhibited the incorporation of glycine-2-C¹⁴ into protein and nucleic acid purines. The other isomer inhibited incorporation into the purines to the same extent, but did not appreciably affect entry into proteins. In lymphosarcoma cells (6C3HED), both isomers were equally effective in inhibiting the incorporation into proteins and purines. Incorporation into guanine was inhibited much more than into adenine. It is suggested that this might indicate tumor inhibiting properties. The levels of the antibiotic necessary to give significant inhibition are much higher than are required to affect bacteria.