Lysosomal activity in aging rat liver: I. Variation in enzyme activity within the liver lobule

The intralobular distribution of three lysosomal enzymes, acid phosphatase, N-acetyl-beta-D-glucosaminidase, and beta-D-glucuronidase, was investigated in hepatocytes of 3-, 12-, 24-, and 36-month-old rats. The distribution pattern changed with age. In young rats, the activity was higher in the peripheral area than in the central area, whereas this situation was reversed in old rats. At all ages, the intermediate area showed the lowest activity. The overall activity increased with age. The reaction product was always present in granules located mainly around the bile canaliculi.