Alteration of lysosomal density by sequestered glycogen during deprivation-induced autophagy in rat liver.

Livers from fed rats were perfused in the single-pass mode with and without 10 mM glucose; autophagy then was induced by deleting amino acids. The decrease in glycogen which occurred in the absence of glucose did not influence the magnitude of the autophagic response, but it did affect the composition of autophagic vacuoles and the distribution of lysosomal marker on isopycnic centrifugation. In livers undepleted of glycogen, amino acid omission shifted a substantial portion of the β-acetylglucosaminidase peak into heavier gradient fractions. This shift was reduced 50% in partially depleted livers and was accompanied by a 40% decrease in glycogen-containing particles. These findings support the notion that glycogen sequestered during autophagy is responsible for the enhanced lysosomal density.