What is the source of calcitonin in the body?

Source of Calcitonin in the Body

Calcitonin is produced by the parafollicular cells (C cells) of the thyroid gland. 1, 2

Primary Production Site

• The parafollicular C cells of the thyroid gland are the primary and most effective source of calcitonin in the body. 3, 4
• These C cells are distinct from the follicular cells that produce thyroid hormone and are predominantly located in the upper portion of each thyroid lobe. 1
• The parafollicular cells secrete calcitonin as a 32 amino acid polypeptide hormone. 2, 4

Secondary Production Sites

• Neuroendocrine cells of the lung and intestine can also produce calcitonin, though to a much lesser extent than thyroid C cells. 1
• Calcitonin is described as a precursor hormone produced by parafollicular cells of the thyroid gland and neuroendocrine cells of the lung and intestine. 1

Clinical Significance

• Calcitonin serves as the primary tumor marker for medullary thyroid carcinoma (MTC), which arises from malignant transformation of these C cells. 1
• Since malignant C cells produce and secrete large amounts of calcitonin, elevated serum calcitonin is a marker for the presence of MTC or metastatic MTC after surgery. 1
• Calcitonin is synthesized in the parafollicular cells and these cells give rise to medullary thyroid carcinoma in both sporadic and inherited forms. 5

Physiological Context

• Calcitonin secretion is stimulated by increases in serum calcium concentration and by gastrointestinal hormones such as gastrin. 3, 4
• The hormone acts through the calcitonin receptor to regulate calcium metabolism and protect against hypercalcemia. 3, 4