Which of the gland secretes calcitonin for regulation of calcium metabolism?

Calcitonin is produced by the parafollicular cells of the thyroid gland, which are also known as the clear or C cells. Its secretion is increased when the thyroid gland is exposed to a plasma calcium level of approximately 9.5 mg/dL. The actions of calcitonin are sho-lived because it has a half-life of less than 10 min in humans. Ref: Barrett K.E., Barman S.M., Boitano S., Brooks H.L. (2012). Chapter 21. Hormonal Control of Calcium & Phosphate Metabolism & the Physiology of Bone. In K.E. Barrett, S.M. Barman, S. Boitano, H.L. Brooks (Eds), Ganong's Review of Medical Physiology, 24e.