A cytochemical study of lysosomal system in rat junctional epithelium after intravenous horseradish peroxidase injection

Abstract

Lysosome formation was studied in rat junctional epithelium (JE) by detection of acid phosphatase (ACPase) using the cerium reaction method after intravenous injection of horseradish peroxidase (HRP). Intravenously injected HRP was endocytosed by the whole JE, especially at the coronal portion. ACPase activity was also observed in numerous organellae (vacuoles, dense bodies, multivesicular bodies and Golgi cisternae) in the junctional epithelial cells. These ACPase positive organellae often fused with each other, and their contents were mixed in the fused structures. The numbers of the ACPase-positive organellae in the HRP-exposed JE were more numerous than those in the JE without HRP, especially at the coronal portion. Thus, the distribution of the ACPase-positive products in the JE was closely related to that of HRP-positive products. These findings indicated that the whole JE has not only endocytotic ability but also intracellular digestion ability by the lysosomal enzymes.