In Vitro Incorporation of Orotic Acid by Spleen and Liver Cells of Rats

Abstract

Summary

Cell suspensions of liver and spleen from rats incorporated labeled orotic acid into RNA when incubated in medium 199 containing 10% rat serum. Two peaks of incorporation were noted in each tissue—one at 3 hr and one at 18 hr of incubation. The rates and the extent of incorporation, however, differed markedly between the two suspensions. Cells from the liver showed a minor early peak and the most pronounced level of incorporated label at 18 hr of incubation, exceeding that of spleen for that time interval by 200-fold. Incorporation at the 3 hr period was consistently lower in cells from spleen than those from liver. This incorporation could be increased in spleen if cells were obtained from animals that had been immunized.