Dose study of 32P incorporation into the nucleic acids of rat lymphoid tissues.

Abstract

SummaryThere was linear incorporation of doses of 32P ranging from 0.191 to 1.91 μCi/g of body weight into DNA, RNA, and the acid soluble phosphorus fraction of the lymph nodes and thymus in rats at 4 and 48 hr after injection. The intercepts of the regression lines of these dose-incorporation curves extrapolated to 0 dose did not differ significantly from 0. These observations indicated that intraperitoneal doses of 32P up to 1.91 μCi/g of body weight did not significantly modify the rate of DNA or RNA synthesis in the lymphoid tissues of rats. There was, however, a highly significant depression of DNA synthesis in the thymus, but not in the lymph nodes 48 hr after the intraperitoneal injection of 9.5 μCi of 32P/g of body weight. It is concluded that doses of 32P up to 1.9 μCi/g of body weight may be used to study nucleic acid synthesis for time intervals up to 48 hr in the lymphoid tissues of rats.