Influence of age and spironolactone on lysosomal enzyme activities, DNA and protein content of the rat liver after partial hepatectomy.

Measurements of DNA and protein content and determinations of lysosomal enzyme activities (beta-glucuronidase, beta-acetylglucosaminidase, cathepsin D) were performed in the rat liver following partial hepatectomy and spironolactone administration. The rats (SIV) were divided into three age-groups: 6 weeks old, 10 months old and 18 months old. 60 h after the administration of spironolactone (2 x 10 mg Aldactone/100 g body weight/day orally via gastric tube for 3 days) partial hepatectomy was performed. The removed two thirds of the liver and the regenerating liver (24 h after partial hepatectomy) were prepared for the biochemical examinations at 4 degrees C. The measurements of the enzyme activities were performed in liver homogenates. The results indicate that the administration of spironolactone cause (1) a weight increase in the normal as well as in the regenerating liver, especially in the older animals; (2) an increase of the protein content of the normal liver in the oldest age-group; (3) a decrease in the DNA content of the normal and regenerating liver of old rats, and (4) an age-dependent increase of decrease of the three lyososomal enzymes beta-glucuronidase, beta-acetylglucosamidase and cathepsin D.