nounIntermediate
Definition
32-amino-acid peptide hormone produced by thyroid C-cells that lowers blood calcium by inhibiting osteoclast bone resorption; salmon calcitonin is used to treat osteoporosis and Paget's disease.

Detailed Explanation

Calcitonin acts as a counterbalance to parathyroid hormone (PTH). When blood calcium rises, C-cells secrete calcitonin, which binds to osteoclast receptors and inhibits their bone-resorbing activity, allowing calcium to remain in bone. Salmon calcitonin is 40–50× more potent than human calcitonin and has a longer half-life, making it the preferred therapeutic form. It's available as injection (Miacalcin) and nasal spray. Calcitonin is also used as a tumor marker for medullary thyroid carcinoma.

Key Facts

  • Calcitonin acts as a counterbalance to parathyroid hormone (PTH)
  • When blood calcium rises, C-cells secrete calcitonin, which binds to osteoclast receptors and inhibits their bone-resorbing activity, allowing calcium to remain in bone
  • Salmon calcitonin is 40–50× more potent than human calcitonin and has a longer half-life, making it the preferred therapeutic form
  • It's available as injection (Miacalcin) and nasal spray
  • Calcitonin is also used as a tumor marker for medullary thyroid carcinoma
Related Terms Parathyroid Hormone Pth Hormone Peptide

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