Autophagosomal glycogen-degrading activity and its relationship to the general autophagic activity in newborn rat hepatocytes: The effects of parenteral glucose administration.

The effects of the administration of parenteral glucose on the postnatal glycogen autophagic activity and its relationship to the general autophagic activity, were studied in newborn rat liver using electron microscopy and biochemical methods. Glucose abolished the normal postnatal hypoglycemia and preserved the hepatocytic hyaloplasmic glycogen to the levels of birth. It also inhibited the normal postnatal increase in the number and volume of autophagic vacuoles. Glucose especially decreased the rate of postnatal development of the glycogen-containing autophagic vacuoles. This decrease was greater than that of the autophagic vacuoles in general. In the control animals at the age of 6 h, the total volume of the glycogen-containing autophagic vacuoles accounted for 87% of the autophagic vacuoles in general, whereas in the glucose-treated animals of the same age, for only 62%. The results of this and previous studies support the view that the general autophagic activity that develops in the immediate postnatal period in rat hepatocytes is mainly expressed as glycogen autophagic activity selectively inhibited by glucose.