Oxidative metabolism in the developing rat kidney has been studied on isolated mitochondria. An increase of about 50% in state 3 respiration has been observed at birth, using succinate, glutamate, or ...palmitoyl-L-carnitine as a substrate. The rate of respiration in the presence of 2,4-dinitrophenol was found identical to state 3 respiration in all cases. Cytochrome oxidase activity did not change between the fetal and newborn stages. The increase of mitochondrial respiration revealed here, which is not linked to a modification of the respiratory chain, could be involved in the rise of kidney ATP level and energy charge observed at birth.
