Erythrocyte nucleotides from control and lead-treated rabbits.

Significant abnormal elevations of the erythrocyte pyrimidine nucleotides UTP and CTP were observed in rabbits after 60 days of oral exposure to lead acetate at a dose of 30 mg/kg/day. No significant changes in purine nucleotides were observed. The increased erythrocyte pyrimidine nucleotides were accompanied by a decrease in red cell pyrimidine 5'-nucleotidase (P5N) activity, an increase in zinc erythrocyte protoporphyrin concentration, and elevated whole blood lead levels. Quantitative measurement of the major 5'-nucleotides in rabbit red cells was achieved by high performance liquid chromatography. The accumulation of UTP and CTP as the results of chronic lead exposure may be explained on the basis of inhibited P5N coupled with the presence of an active nucleoside diphosphokinase.