Effect of N-2-fluorenylacetamide on rat lysosomal acid phosphatase

Abstract

Administration of a single oral dose of 500 mg/kg of N-2-fluorenylacetamide (AAF) to rats was shown to cause a depression of about 50% in lysosomal acid phosphatase activity. The effect was restricted to the enzyme of the liver and kidney. Other tissues rich in lysosomal acid phosphatase were not affected. The effect appeared to be specific for lysosomal acid phosphatase, as other lysosomal enzymes, e.g., acid ribonuclease, aryl sulfatase, β-glucuroni-dase, and cathepsin, were not affected, nor were enzymes characteristic of the other principal subcellular fractions. The depression of enzyme activity reached a maximum 10 hours after administration of AAF, persisted for 5 days, and returned to normal within the next 2 days. Neither AAF nor its principal urinary metabolite, hydroxy-AAF, inhibited lysosomal acid phosphatase in vitro, nor was it possible to demonstrate the presence of an inhibitor in the liver of treated animals. The possibility that the marked decrease in activity of the lysosomal acid phosphatase may be due to a specific inhibition of its synthesis is discussed.