Hepatic lysosomal enzymes in young rats fed retinol.

Oral administration of one dose of 6.0 and 12.0 mg retinol for one day significantly increased percentage free activities of protease (cathepsins), cathepsin B1 and acid ribonuclease, whereas feeding of one dose of 1.5 mg retinol for one day did not release the above enzymes in younger rats. However, feeding of 1.5, 6.0 and 12.0 mg retinol daily for two days did not significantly increased the percentage free activities of these lysosomal enzymes except that of acid ribonuclease which was still increased in young rats fed 12.0 mg retinol. Retinol feeding either for one day or two days did not affect the release of acid phosphatase and aryl sulphatase in young rats. Retinol inhibited in vitro the activities of protease (cathepsins) and cathepsin B1.