[Changes in lysosome enzymatic activity during fasting following a regimen of once-a-day or all-day feeding].

The influence of fasting for 24-96 hours is studied in rats, subjected in advance to a regimen of all day long access to food, to a single feeding in 24 hours. Total activity of beta-N-acetylglucosaminidase (beta-N-AcG1), acid phosphatase (AP) and beta-glucuronidase, as well as the free activity of the first two enzymes are studied in liver homogenate. The activity of beta-N-AcG1 is determined in blood serum also. A rise of total beta-N-AcG1 activity is recorded in liver homogenate, increasing parallel to prolongation of the fasting period. The changes in free activity of AP and beta-N-AcG1, and in the plasma activity of the latter enzyme are similar. The above described changes are more strongly pronounced in the groups subjected in advance to a single feeding regimen. These changes are interpreted as an expression of the active participation of lysosomes and their enzymes in the transition to endogenic nutrition. The lysosome membrane proves to be more vulnerable to damage by starvation among the animals previously maintained on a single feeding regimen.