Impact of lead on nucleic acids and incorporation of labelled amino acid into protein.

The effects of high administration of lead acetate (3.4 mg/100 g of body weight) for a period of 4 days were studied in albino rats. The weights of lead treated rats were not affected while the liver showed enlargement following treatment. Administration of lead reduced the protein content of liver and concentration of DNA decreased to a slight extent. Protein/DNA ratio in liver remained unaltered and this unaltered protein/DNA ratio following lead treatment suggested nonimpairment of cellular protein concentration. The RNA content of liver was increased following treatment and protein/RNA ratio was reduced. RNA per unit amount of DNA was found to be increased and this increased cellular concentration of RNA might result from the degradation of RNA. Lead administration caused a reduction in the incorporation in vivo 14C-leucine into protein of liver. It has been suggested that the diminished incorporation of amino acid into protein following lead treatment might be affected at the translational level of protein biosynthesis.