title: The transcription of various types of ribonucleic acid by hepatocytes isolated from rats of various ages.
abstract: The synthesis of various types of ribonucleic acid (RNA) isolated from 6- to 3-month-old female Fischer F344 rats was compared. The rate of RNA synthesis by freshly prepared hepatocytes was determined by dividing the amount of [3H]orotic acid incorporated into RNA as uridine-5'-monophosphate by the specific activity of the uridine-5'-triphosphate pool. The rate of total RNA synthesis by hepatocytes from 19-month-old rats was 40% less than the rate for hepatocytes from 12-month-old rats. No significant difference in the rate of total RNA synthesis was observed between 19 and 30 months of age. The percentage of [3H]orotic acid incorporated into poly(A) + RNA by 30-month-old rats was approximately 50% less than that observed for hepatocytes isolated from 6-month-old rats. The percentage of [3H]orotic acid incorporated into poly(A)-RNA as ribosomal RNA (38S, 18S, and 5S RNAs) or transfer RNA was similar for 12- and 30-month-old rats. The rate of poly(A) + RNA synthesis by hepatocytes isolated from 30-month-old rats was 65% less than that observed for hepatocytes from 6-month-old rats. In contrast to total RNA synthesis, the rate of poly(A) + RNA synthesis for the 30-month-old rats was significantly less than the rate for 19-month-old rats.
mesh_terms: D000367:Age Factors; D000375:Aging; D000818:Animals; D005260:Female; D066298:In Vitro Techniques; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D009963:Orotic Acid / Q000032:analysis; D012313:RNA / Q000096:biosynthesis*; D051381:Rats; D011916:Rats, Inbred F344; D014158:Transcription, Genetic
chemical_list: D009963:Orotic Acid; D012313:RNA