Chemical Identity

Property	Value
Chemical Formula	C145H240N44O48S2
Molecular Weight	3432 Da
CAS Number	47931-85-1
Peptide Class	Polypeptide Hormone (32 amino acids)
Sequence	CSNLSTCVLGKLSQELHKLQTYPRTNTGSGTP-NH2

Structure

Salmon calcitonin is a synthetic 32-amino acid polypeptide with a 1-7 disulfide bridge and C-terminal prolinamide. It differs from human calcitonin at 16 of 32 positions, conferring 20-100-fold greater potency due to stronger receptor binding and resistance to degradation.

Mechanism of Action

Salmon calcitonin binds to calcitonin receptors on osteoclasts, activating adenylyl cyclase and reducing osteoclast motility, polarization, and ruffled border formation. This rapidly inhibits bone resorption. It also has analgesic effects on bone pain through central calcitonin receptors.

Clinical Applications

• Postmenopausal osteoporosis: When other agents not tolerated
• Paget’s disease: Bone remodeling disorder
• Hypercalcemia: Acute management
• Bone pain: Analgesic effect in osteolytic metastases and fractures

Pharmacokinetics

• Half-life: 43 minutes (injection), 16 minutes (intranasal)
• Tmax: 16 minutes (SC)
• Bioavailability: 65% (SC), 3-5% (intranasal)
• Metabolism: Kidney, blood, peripheral tissues
• Route: SC, IM, intranasal

Safety and Side Effects

Nausea (10%), flushing (2-5%), nasal irritation (intranasal), antibody formation (rare with salmon peptide), and hypocalcemia. Tachyphylaxis limits long-term efficacy.

References

• Chesnut, C.H., et al. (2000). PROOF trial: nasal calcitonin for osteoporosis. Bone, 27, 561-568.
• Overgaard, K., et al. (1992). Effect of calcitonin on vertebral fractures. BMJ, 305, 556-561.