QUANTITATIVE RELATIONSHIPS BETWEEN MITOCHONDRIAL POPULATIONS AND ENZYME ACTIVITIES IN THE LIVER OF THE POSTNATAL RAT.
ARMY MEDICAL RESEARCH LAB FORT KNOX KY
Pagination or Media Count:
Mitochondria in sections of liver samples from newborn and weanling 26 day rats were analyzed in quantitative electron microscopy. Specific activities of the mitochondrial enzymes, NADH-cytochrome c reductase, succinate-cytochrome c reductase, and cytochrome oxidase, were determined in similar samples. During the postnatal period the number of mitochondria per unit volume of cytoplasm increased 2.6 times while the volume of the average mitochondrion decreased 0.58 times resulting in a net increase of 1.4 in the size of the mitochondrial compartment. The decrease in volume of the average mitochondrion was the result of a decrease in the number of large mitochondria and an increase in the number of small mitochondria. These data indicate mitochondrial biogenesis in rat liver during postnatal development. The increase in the mitochondrial compartment was paralleled by increases of 1.8 - 2.1 times in the specific activities of the mitochondrial enzymes. Author