RNA and Protein Synthesis in Normal Peripheral Mononuclear Leukocytes

Abstract

Peripheral leukocytes were incubated with either H3-cytidine or H3-leucine, and radioautographs were prepared. Mononuclear cells were subdivided into seven groups, according to their morphology, and the mean percentage of labelling and the mean grain count for each group was obtained. No direct relationship was observed between H3-cytidine and H3-leucine uptake. While in some types of cells, such as the monocytes, this ratio amounted roughly to one, in other types of cells, such as the circulating cells of "blastic" type, the ratio was much higher. It is emphasized that in large lymphocytes the cytidine/leucine ratio resembles that observed in monocytes, while in small lymphocytes the ratio is similar to that of the cells of "blastic" type. It is assumed that in resting blood cells with high H3-cytidine and low H3-leucine uptake, the metabolic processes of the nucleolus and the associated structures represent the main nuclear activity.