A Histochemical Study on the Activity of Several Enzymes in Rat Liver Tissues with Special Reference to the Age-factor!). 2) By

It has been known to certain extent that aging of the animal, one of the interesting biological phenomena, is associated with morphological and physiological changes in various organs _ However, very little has been known about the relationship between aging process and enzymatic activity histochemically. It is then evident that the histochemical approach is needed for elucidation of this problem. The author (Matsuzawa 1964a) has reported that the activity of glucose-6-phosphatase (G-6-Pase) and of phosphorylase varies with glycogen content in rat livers in connection with the increase in age of rats, and that intra-lobular distribution of these enzyme activities became heterogeneous with age: namely in old rats the G-6-Pase activity is higher in periportal areas of hepatic lobules than in central areas, while it is evenly distributed throughout the lobule in young rats. The present paper describes additional data pertaining to some histo-chemical changes occurring in rat livers in relation to age, with special attentio