Rates of protein synthesis by intact liver parenchymal cells isolated from male Fischer F344 rats ranging in age from 2.5 to 30 months were determined by measuring the incorporation of [3H]valine into acid-insoluble material and the specific activity of the extracellular valine. The rate of protein synthesis decreased 44% from 2.5 to 18 months and then increased slightly (18%) from 18 to 30 months. There was no dramatic change in the types of proteins synthesized by isolated liver parenchymal cells isolated from 2- or 18-month-old rats as determined by SDS-polyacrylamide gel electrophoresis. The ribosomal-transit time by liver parenchymal cells isolated from 18-month-old rats was 60% higher than the ribosomal-transit time of liver parenchymal cells isolated from 4-month-old rats. The fidelity of protein synthesis by parenchymal cells isolated from 4- and 18-month old rats was compared by measuring the incorporation of p-fluorophenyl-alanine (an analogue of phenylalanine) into acid-insoluble material. Although protein synthesis decreased significantly from 4 to 18 months, the fidelity of protein synthesis remained constant.
ASJC Scopus subject areas
- Developmental Biology