calcitonin

Calcitonin is a HORMONE secreted by the PARAFOLLICULAR CELLS (C CELLS) of the THYROID GLAND in response to increased BLOOD CALCIUM LEVELS. It plays a role in maintaining CALCIUM HOMEOSTASIS by inhibiting the activity of OSTEOCLASTS, the bone-resorbing cells responsible for breaking down BONE TISSUE and releasing calcium into the bloodstream. By reducing BONE RESORPTION, calcitonin decreases calcium release from bones and promotes lower calcium concentration in the blood. Its actions oppose those of PARATHYROID HORMONE (PTH), which increases blood calcium levels. Abnormal calcitonin production is clinically important in conditions such as MEDULLARY THYROID CARCINOMA, where calcitonin may be used as a TUMOR MARKER.

Calcitonin is a hormone made by the thyroid gland that helps lower the amount of calcium in the blood by reducing calcium release from bones.

• Calcitonin is a hormone involved in calcium regulation. • It is produced by special thyroid cells called parafollicular cells or C cells. • It is released when blood calcium levels become high. • Its main actions include: - Slowing down osteoclast activity. - Reducing breakdown of bone tissue. - Decreasing calcium release from bones into blood. • Calcitonin works opposite to parathyroid hormone (PTH). • It helps maintain the balance of calcium needed for normal body function. • High calcitonin levels can be associated with medullary thyroid carcinoma. • Calcitonin measurement can be useful as a clinical marker in certain thyroid diseases.