Acid hydrolases of the rat uterus in relation to pregnancy, post-partum involution and collagen breakdown

Publisher Website
Google Scholar
Abstract
The rat uterus contains acid cathepsin, [beta]- glucuronidase, [beta]-galactosidase, acid phosphatase and deoxyribonuclease II at concentrations comparable with those found in liver. Two non-hydrolytic uterine enzymes, cytochrome c oxidase and aspartate amino-transferase, display only 2-6% of the activity found in liver. The concentrations of acid cathepsin and [beta]-glucuronidase are significantly decreased in pregnancy and increase 3[long dash]4-fold during post-partum involution. The concentrations of [beta]-galactosidase and acid phosphatase are not decreased in pregnancy and increase only 2[long dash]3-fold during involution. The concentrations of these 4 acid hydrolases increase linearly during the 1st 4 days post partum and reach their peak values at the same time that wet weight and collagen content fall to their lowest point. The concentration of deoxyribonuclease is depressed in pregnancy but does not rise above normal in the post-partum period. Only a small proportion of each hydrolytic activity can be isolated in the mitochondrial[long dash]lysosomal fraction of sucrose homogenates of the rat uterus. This proportion increases during involution. However, the extensive mitochondrial rupture occurring during homogenization indicates that the technique is probably too harsh to obtain a true measure of the proportion of lysosomes present in the intact tissue. There are no significant changes in either the concentration or subcellular distribution of the 5 acid hydrolases in the livers of the experimental rats during pregnancy or involution. In each case the largest proportion of the activity is found in the mitochondrial-lysosomal fraction of liver homogenates. The results are interpreted in terms of the lysosomal theory of intracellular digestion.