Peroxisomes of rat peritoneal macrophages during phagocytosis.

The peroxisomes of resident macrophages in the rat peritoneal cavity were examined during the phagocytosis of latex microbeads, employing the akaline diaminobenzidine (DAB) technique. Peroxisomes generally were located in close proximity to phagosomes and were often observed in a process of apparent fusion with phagosomes. Cytochemical evidence was also obtained for discharge of catalase from peroxisomes to phagosomes. The profiles indicating fusion were observed after 10 minutes of incubation with microbeads. The number of peroxisomes was increased in macrophage profiles examined 30 minutes after exposure to microbeads. Acid phosphatase was localized in small vesicles that were distinct from peroxisomes, and peroxidase was not demonstrable in peroxisomes. A method for ultrastructural localization of periodate reactive complex carbohydrate demonstrated glycoproteins in numerous small vesicles or granules, some of which possibly represented peroxisomers. The possible function of peroxisomes during phagocytosis in rat peritoneal macrophages is considered.