Human Calcitonin (hCT)

Human Calcitonin (hCT) is a 32-amino acid hormone peptide belonging to the Calcitonin/Calcitonin-gene related peptide (CGRP) family, that also comprises amylin, adrenomedullin (AM) and adrenomedullin2/intermedin (AM2/IMD). Calcitonin is characterized by a N-terminal disulfide bond that forms a 7 amino acid ring structure, a region with a α-helix tendency and an amidated C-terminus1. Calcitonin peptide is produced by C cells of the thyroid gland and binds preferentially to the G-protein coupled receptor, calcitonin receptor (CTR)1. Calcitonin receptor signals through activated Gs protein and the production of cAMP second messenger molecules by adenylyl cyclase1. The dissociation constant (Kd) of calcitonin receptors expressed by a human ovarian small cell carcinoma line is approximately 4.6 nM for human Calcitonin2. Calcitonin is involved in the homeostasis of calcium and phosphorus, and the regulation of bone dynamics. At the basal state, calcitonin secretion reduces plasma calcium and phosphorus levels, and promote bone formation. In Calca -/- mice, a murin particle-induced osteolysis model, Calcitonin peptide has been used as a test compound for studying the effects of calcitonin deficiency. It has been shown that artificial calcitonin subsitution inhibits bone resorption by reducing the formation of osteoclasts and thereby the resulting osteolytic reaction3. The Hypocalcemic Human calcitonin was also used as a positive control to monitor changes in serum calcium levels in HHD transgenic mice vaccinated with Parathyroid hormone-related protein (PTH-rP)-derived peptides in the context of anti-cancer immunotherapy study4. Moreover, it has been reported that calcitonin peptide is a potent stimulator of uncapacitated mouse spermatozoa by regulating a specific isoform of adenylyl cyclase and the production of cAMP, which plays a pivotal role in mammalian sperm function5. sb-PEPTIDE provides stable isotope labeled calcitonin peptide. This peptide has been quantified accurately using amino acid analysis.