[Effect of short-term fasting on liver lysosomes in rats, biochemical studies (preliminary report)]

The total activity of four lysosome enzymes--acid phosphatase, beta-glucuronidase, alpha-glucosidase and beta-N-acetylglucosaminidase--is studied in liver homogenate at 2, 6, 24 and 48 hours after the last meal in rats, previously sustained on a single-daily-feeding regimen. In addition, the free activity (percentage of the total) of the latter enzyme and its activity in the serum as well are investigated. A rise of the total activity of the first three enzymes is recorded within 48 hours after the beginning of starvation. The free activity of beta-N-acetylglucosaminidase shows an increase at 48 hours, while its activity in the serum--as early as 24 hours. The changes described above are interpreted as an expression of lysosome membrane permeability enhancement under fasting conditions.