A morphometric study of the inhibition of autophagic degradation during restorative growth of liver cells in rats re-fed after starvation.

In the parenchymal cells of the liver of adult male rats re-fed on the evening of the fifth day after a period of absolute starvation, a nearly complete absence of autophagic vacuoles (AV) has been found by the morphometric determination of the fractional cytoplasmic volume of AV. The mean value for that parameter increased only gradually during periods of re-feeding. The value was found to be in the range of the control values only on, or after, the fifth day of re-feeding. As in previous experiments, in the control animals the number of AV was again found to be dependent on a circadian rhythm with maxima during the light, and minima during the dark, periods. This rhythm reappeared in the period of re-feeding without a shift in phase. In the controls as well as in the re-fed animals the "segregated fraction" was highest for microbodies, intermediate for mitochondria and glycogen, but rather low for the remaining components of the cytoplasm. It is suggested that the long term inhibition of cellular autophagy, found in the present study, plays an important role in the restorative cellular growth of the liver during the recovery from the atrophy induced by starvation.