Age changes of turnover rates and subfraction composition of rat liver and spleen histones.

Histones from tissues of young and old rats have been compared. Lysine-rich F1 histone was found to be the only one which is tissue specific and whose subfraction pattern changes in old cells. The comparison of turnover rates of different histones from liver and spleen, measured by the level of 3H-leucine incorporation and subsequent decay of its specific activity with time, showed that while the activity and turnover or arginine-rich histones F3 and F2a2 was reduced in old liver, ageing was associated with increased turnover of F1 histone. The results are discussed from the point of view of a special role of F1 histone in the condensation of chromatin and in the age-related inhibition of some cellular functions.