Effect of maternal dietary deficiency on the metabolism of high-molecular weight, soluble and transfer RNA in the liver of the 21-day-old offspring of rats

Abstract

The 21-day-old male progeny of dietary-restricted rats were administered 14C-orotic acid intraperitoneally to study the metabolism of high-molecular weight soluble (sRNA) and transfer RNA (tRNA) in their livers, which were removed at various time intervals ranging from 6 to 120 minutes after the injection. DNA and total RNA were extracted from each liver sample, and nucleic acids were fractionated with 2M NaCl into insoluble (high-molecular weight) and soluble (DNA and tRNA) fractions. All the preparations were analyzed by sucrose density gradient sedimentation, and the distribution of radioactivity was determined. Dietary-restricted progeny experienced significant increases of RNA (p<0.001), including high-molecular weight sRNA (p<0.001) and tRNA components (p<0.001). The greatest increases were apparent in the tRNA and 4–18s RNA fractions. Dietary restriction during the period of growth, gestation and lactation caused a significant reduction in total body weight and liver weight in the 21-day-old progeny. It also enhanced the rate of RNA synthesis in the livers of these animals. The ratios of DNA/total RNA were not affected by dietary deprivation of the progeny, inferring and confirming the observation noted above that the progeny must have experienced augmented RNA degradation and elevated biosynthesis of various forms of RNA.