Influence of age and of short-term and repeated fasting on the cytochrome concentration in mitochondria isolated from different parts of the rat CNS and liver.

The authors measured the cytochrome a+a3, b and c+c1 content of mitochondria isolated from the cerebral cortex, subcortical structures, medulla oblongata and liver of male rats aged 5 and 60 days. They found that the amount of cytochrome a+a3, b and c+c1 in the cerebral cortex, of cytochrome a+a3 and b in subcortical structures and of only cytochrome a+a3 in medulla oblongata and liver mitochondria rose during ontogenesis. A single short-term (24 h) fast reduced the cytochrome a+a3 and b content of the cerebral cortex and the cytochrome a+a3 content of the medulla oblongata in 5-day-old rats. In 60-day-old animals, there was a drop in the cytochrome a+a3 and b concentration in the cerebral cortex and in the a+a3 concentration in liver mitochondria. Repeated fasting (3 X 18 hours) reduced the cytochrome a+a3 content of mitochondria isolated from all the given parts of the CNS in 5-day-old rats.