Effect of paraquat on the biosynthesis of deoxyribonucleic acid, ribonucleic acid and protein in the rat

Abstract

This study was designed to determine the relative subcellular distribution of paraquat and the effect of paraquat on the biosynthesis of DNA, RNA and protein in rat lung, liver and kidney. Biochemical parameters were correlated with the clinical syndrome. Paraquat was found in all the major cellular fractions at various times after administration of 126 mg/kg by gabage and no evidence of significant accumulation in any subcellular fraction was present. l-Leucine incorporation into protein was increased ( P < 0·05) in the lung, liver and kidney 32 hr after paraquat administration, and in the lung, protein synthesis was still increased at 128 hr ( P<0·05). DNA biosynthesis was significantly decreased in the three organs 32 hr after paraquat treatment. In the kidney, this reduction was also significant at 64 hr. The rate of RNA synthesis was significantly decreased at 16 hr in the liver and kidney. The biochemical changes correlated in time with the histopathological changes induced by paraquat and preceded clinical signs of toxicity by 1–2 days.