Uptake of peroxidase by calcitonin inhibited osteoclasts.

The present electron microscopic histochemical study demonstrates that osteoclasts from calcitonin treated bone are able to take up organic macromolecules even though the ruffled border has disapppeared. The absorption occurs around the entire periphery of the osteoclast, but the amount of absorbed peroxidase seems to be reduced in comparison with that of untreated cells. It is concluded that the effect of calcitonin on osteoclasts is primarily a cessation of the exocytosis and the concomitant disappearance of the ruffled border.