Ultrastructural studies on diurnal variations in mitochondria in various regions of the hepatic lobule

Stereologic studies on diurnal variations in ultrastructural manifestations of hepatic mitochondrial function in various regions of the hepatic lobules were performed. The experiments were performed on Wistar rats in May when the liver shows the maximal content of glycogen. The materials for the studies were taken at 8 am. and 10 p.m. The stereologic examinations were done according to the method of Weibel et al. The results obtained may suggest a conversion of the orthodox hepatic mitochondria to the transitional state, that is during the glycogen minimum in the rats in May. In the morning, when the glycogen deposits increased, the pericentral mitochondria are in the orthodox state. In the evening glycogen consumption due to glycogenolysis was accompanied by conversion of the mitochondria from the orthodox state to the transitional ones, which may suggest their increased metabolic activity.