The Effect of Cortisone Acetate on Lysosomal Enzyme Levels In Rat Liver

Abstract

Increases in the levels of four lysosomal enzymes were measured during the induction of tyrosine transaminase in rat liver by cortisone acetate. Tyrosine transaminase showed a maximum specific activity 2 h after the injection of the steroid hormone whereas lysosomal enzyme levels reached a maximum specific activity at 4 h. The maximum increase in specific activity for 15 injected animals compared to 15 controls was 100% for tyrosine transaminase; 40% for cathepsin A, cathepsin D, and β-N-acetylglucosaminidase; and 10% for acid phosphatase. Increased specific activities from livers of cortisone-acetate-treated rats were observed when lysosomal enzymes were released both by detergent treatment and by freezing and thawing.The increased specific activities were found in the readily solubilized lysosomal enzyme fractions and not in those lysosomal enzyme fractions which remain associated with particulate matter after lysosomal disruption. Similar increased specific activities for acid phosphatase and β-N-acetylglucosaminidase were observed in cultures of Morris hepatoma cells from rat liver when incubated with cortisone acetate in vitro. Thus the response appears to be typical of single cell types.