Determination of Degradation Rates of Transfer and Ribosomal Ribonucleic Acids in Cultured Rat Hepatocytes by MeasuringN6-Threoninocarbonyladenosine, Dihydrouridine, and Pseudouridine in Medium Using High-Performance Liquid Chromatography

Abstract

Modified ribonucleic acid catabolites excreted into the medium by primary cultures of rat hepatocytes (2.3 ± 0.42 × 106cells/dish) during a 24-h cultivation period were quantified by reversed-phase high-performance liquid chromatography (fmol/103cells): 613 ± 81 dihydrouridine, 46 ± 6N6-threoninocarbonyladenosine, 1879 ± 220 pseudouridine. On the basis of these excretion rates and the average frequency of occurrence of these modified ribonucleosides per cytoplasmic transfer ribonucleic acid (residues: 2.6 dihydrouridine, 0.22N6-threoninocarbonyladenosine, 3 pseudouridine) as well as per cytoplasmic ribosomal ribonucleic acid (residues: 95 pseudouridine), the degradation rates of transfer and ribosomal ribonucleic acids were calculated. The degradation rate of transfer ribonucleic acid (fmol/103cells/24 h) was 236 ± 31 (via dihydrouridine) and 211 ± 28 (viaN6-threoninocarbonyladenosine) and that of ribosomal ribonucleic acid (fmol/103cells/24 h) was 13.1 ± 1.7 (via pseudouridine andN6-threoninocarbonyladenosine).