RNA Metabolism in Lymphocytes Stimulated by Phytohemagglutinin: Initial Responses to Phytohemagglutinin

The initial changes in lymphocyte RNA metabolism produced by treatment with phytohemogglutinin (PHA) are described. The earliest change was a decrease in total RNA (i-RNA), detectable after 30 minutes of exposure to PHA. This loss could not be localized to any of the major types of cellular RNA. After 1 hour, accelerated synthesis of RNA, shown by incorporation of u-H³, was detected, and a progressive increase in rate of synthesis continued for 24 hours.

The significance of the early loss of RNA as related to the onset of lymphocyte growth is discussed.