[Action of calcitonin on osteoclasts in Paget's bone disease during long term treatment (author's transl)].

Comparison of biopsies from patients with Paget's bone disease before and during long-term treatment with calcitonin reveals that the ration of bone-adherent osteoclasts to free osteoclasts is not modified by the hormone. Nor does treatment alter the average number of nuclei in osteoclasts. Under electron microscopy, all the cytological anomalies of osteoclasts in Paget's bone disease and, in particular, the characteristic nuclear inclusions, persist through treatment. Thus, although such osteoclasts do react to calcitonin as demonstrated by several authors, the specific morphological anomalies remain unaffected by the treatment. It is likely that the osteoclast in Paget's bone disease is an abnormal cell with peculiarities which may be related to the yet unknown etiology of the disease.