AGE AFFECTS BRAIN PROTEIN-SYNTHESIS IN RATS

The purpose of the present study was to determine whether age affected the rate of brain protein synthesis in rats. Experiments were conduct ed on three groups of rats, ages 4, 7 or 24 wk. The fractional rates o f protein synthesis in brain, liver and kidney decreased and the RNA c oncentration (mg RNA/g protein) declined with age. In brain, liver and kidney, the RNA concentrations were significantly correlated with the fractional rates of protein synthesis. The RNA activity [g protein sy nthesized/(g RNA.d)] was not related to the fractional rate of protein synthesis in any organs except cerebral cortex. The results suggest t hat the rate of protein synthesis in brain declines with age after wea ning, and that RNA concentration is at least partly related to the fra ctional rate of brain protein synthesis.