[Hormones and osteoporosis update. Calcitonin, CGRP and bone].

Calcitonin is the hormone secreted from parafollicular cells in the thyroid and inhibits osteoclast activity, leading to reduced bone resorption and low levels of serum calcium. Calcitonin is approved to use for osteoporosis and hypercalcemia. However, its effect on the prevention of bone fracture is still controversial, although bone mineral content is apparently improved. The same gene, CALCA, encodes another active peptide, calcitonin gene related peptide (CGRP). CGRP has been reported to promote bone formation based on the high bone mass phenotype of CALCA - deficient mouse.