[The spatial distribution of mitochondrial respiration and oxidative phosphorylation along the small intestine in rats of different ages].

Growing rats were shown to have the maximum of respiratory and ATP-synthetase activities in the duodenum and proximal part of the small intestine, the minimum--in its distal part, whereas the medial part of the intestinal tube was in intermediate position. These parameters were equally distributed along the small intestine in adult rats. In old rats, the highest rate of oxygen consumption was revealed in the mitochondria of the medial part, the lower one--in the proximal part, and the lowest level was found in the duodenum and in distal part of the small intestine.