Mechanism of Oxidation of Cytoplasmic Reduced Nicotinamide Adenine Dinucleotides in the Developing Rat Liver

A Morphometric and Biochemical Study of Fetal and Adult Rat Liver Cells, with Special Reference to Energy Metabolism

“…Compared with the adult rat liver cell the nucleus occupies a much higher volume fraction of the fetal rat liver cell, while the mito chondria take a much smaller volume fraction. The latter is to be expected, in view of the observation that the number of mitochondria per fetal liver cell is lower than that of the adult rat liver cell [22].…”

“…It is now also possible to recalculate the earlier determinated number of mitochondria per cell [22] to 'concentration' of mito chondria in the cytoplasm. This value will ultimately determine the oxidative capacity of the cell.…”

The Development of some Krebs Cycle Enzymes in Rat Liver Mitochondria

“…In figure 6 the development of the cytoplasmic isozyme is shown. It is now possible to calculate the activity of this enzyme in the different cell compartments, taking into account the number of mito chondria per cell [24] and the number of cells per gram wet weight of tissue [29]. The results are shown in table II.…”

“…The question arises however whether this lower activity is limited to iso lated mitochondria or to the cell as such. Table II illustrates that, despite the lower activity of succinic dehy drogenase per mitochondrion [10] and the lower number of mitochon dria per liver cell [24], the succinic dehydrogenase activity per gram wet weight of liver is the same for fetal and adult rat liver. It is known that rapidly dcviding tissues carry out oxidative phosphorylation in the nucleus: the thymocyte is a specific example [25].…”

Size of L-Lactate Transport from the Fetal Rat to the Mother Animal

“…This fact is supported by the absence or low activities of some of the citric-acid-cycle enzymes [3,4] in the fetal hepatocytes during the third week of gestation, together with a smaller number of mitochondria [5] in these cells. Consequently the fetal rat better survives an anoxic period than the adult animal.…”