Light and electron microscopic study on the osteoclastic phagocytosis of cells in the rat.

By means of micromorphological and cytochemical investigations of the tibia metaphyses of growing rats the phagocytosis of cells by multinucleated osteoclasts could be demonstrated. On the average 1.9% of osteoclasts exhibited included cells. With very few exceptions the phagocytosed cells belonged to the monocyte/macrophage lineage, as shown by evidence from the ultrastructure. After the animals were treated with parathyroid hormone the number of osteoclasts increased significantly, but not, however, the number of osteoclasts with a cell inclusion.