Calcitonin(swine)

Physiological Roles and Mechanisms of Calcitonin

Davey, Rachel A., et al. Journal of Bone and Mineral Research, 2013, 28(5), 973-979.

The physiological role of calcitonin in regulating bone and calcium homeostasis has been controversial, and elucidating the physiology of calcitonin is important for understanding the overall calcium homeostasis in the body. This work proposes that calcitonin has two different but related roles, first to protect bone by regulating bone turnover, and second to maintain calcium homeostasis.
Physiological Roles of Calcitonin
· The best understood role of calcitonin and the most comprehensive data is its role in inhibiting osteoclast activity and thus inhibiting bone resorption. This inhibitory effect has been demonstrated in vivo, in bone organ cultures, and in isolated osteoclasts in vitro. Calcitonin has also been shown to affect the body's handling of calcium by promoting calcium excretion by the kidneys, possibly through its role in reducing renal tubular calcium reabsorption.
· Recent research using genetically engineered mouse models has revealed additional functions of calcitonin through its receptor (CTR) that have a significant impact on the regulation of bone and calcium balance. Mice lacking CTR in osteoclasts are more prone to induced hypercalcemia, while administering exogenous calcitonin is effective in reducing serum calcium levels in younger animals.
· Calcitonin is also involved in protecting the skeleton from excessive bone mineral loss during periods of high calcium demand, such as lactation. The effects of calcitonin in protecting maternal bone during lactation are thought to be mediated solely through inhibition of osteoclastic resorption.