RNA metabolism in the guinea pig infected with the nematode Trichostrongylus colubriformis

The concentration of RNA/mg DNA fell progressively in skeletal muscle, but was unchanged in the liver during infection of the guinea pig by the nematode Trichostrongylus colubriformis. The rate of RNA turnover was increased in muscle and liver.The specific activity of RNA 24 hr after the injection of ³H-uridine was unchanged in muscle, but increased in liver. While the concentrations of RNA precursors were unchanged in liver. The activity of muscle RNA polymerase was decreased, but that of liver was unchanged by the infection.From these results, it was concluded that the fall of the concentration of muscle RNA was due to both the increased rate of turnover and a decreased rate of synthesis, whereas the increased rate of turnover of liver RNA was approximately equal to the increased rate of synthesis.The significance of these findings is discussed in relation to changes of muscle and liver protein metabolism in this nematode and in bacterial or viral infections, as well as those that occur following reduced feed intake.