Morphometric Studies on the Age Changes of Mitochondria in the Proximal Tubules of Rat Kidneys

Abstract

Morphometric studies have been made on age changes in the epithelial cell mitochondria of the proximal tubules of rat kidneys in relation to their function.
Mitochondrial volume per cell was significantly larger in 12 and 18 month old rats than in 2 and 25-29 month old rats. Total volume of mitochondria in the convoluted tubuli of the kidney was estimated to be maximum in the 18 month old rats, and the volume significantly decreased in the 25-29 month old rats; the mitochondrial cristae were arranged most sparsely in the former cases and become to be significantly compact in the latter. From above, each mitochondrion of the renal convoluted tubuli seems to function more actively in the 25-29 month old rats, in which the number of the convoluted epithelial cells is significantly smaller than in the 18 month old ones.