Rat brain protein synthesis declines during postdevelopmental aging.

Using improved methods to measure brain protein synthesis in vivo (Dunlop et al., 1975) we have established that brain protein synthesis significantly declines in forebrain, cerebellum and brain stem when mature rats (3 months old) are compared to old rats (22.5 months old). The incorporation of (3H) L-lysine into forebrain protein is reduced 11% in 10.5 month old rats compared to 3 month old rats. A further reduction of 9% occurred between 16.5 months and 22.5 months. Our data suggest that reduced levels of protein synthesis initiation may be responsible, at least in part, for this age-related decline.