Age dependent kinetic studies of cytoplasmic and lysosomal enzymes of the normal and D-galactosamine injured rat liver.

Rats of two age groups (6 weeks and 30 months) received (1) a single dose of 600 mg D-galactosamine (GalN)/kg body weight by intraperitoneal (i.p.) injection, (2) a single dose of 600 mg GalN/kg body weight i.p. combined with 20 mg prednisolone/kg body weight subcutaneously at the beginning of the experiment. The kinetic studies disclose that GalN produces more severe changes in old than in young animals, represented by the activities of cytoplasmic (glutamic oxaloacetic transaminase, glutamic pyruvic transaminase) and lysosomal (beta-acetylglucosaminidase beta-glucuronidase, cathepsin D) enzymes. Prednisolone diminishes the morphological liver changes as well as the biochemical disturbances in young rats. There is only a protecting effect in morphological changes of old animals within the first 12 h. The prevention of cytoplasmic enzyme activity increase is limited to the first 12 h.