Calcitonin

Calcitonin is a peptide hormone that appears to play a minor or short-term modulating role in calcium metabolism, but may have other functions as well. Its synthesis and metabolism are similar to those of other peptide hormones in many respects. Copp et al. reported their discovery of a hypocalcemic principle liberated from the thyroid-parathyroid system of dogs in perfusion studies. They presumed that it came from the parathyroids, and named it “calcitonin”. Calcitonin is a 32 amino acid residue peptide chain with a single disulfide linkage between cysteine residues at positions 1 and 7. The mol wt of this material is approximately 3500 daltons. In species characterized to date, the carboxyl-terminal residue is always a prolinamide, and any shortening or modification at this end of the molecule destroys biologic activity. Several studies suggest that the adrenergic system may play a physiologic role in control of calcitonin.