Calcitonin is secreted by:
Calcitonin is primarily secreted by the parafollicular C cells of the Thyroid gland. It is a hormone secreted in response to elevated blood calcium. It stimulates calcium deposition in bone and calcium excretion by the kidneys, thus reducing blood calcium. Ref: Essentials of Pharmacology By K D Tripathi, 5th, Edition, Page 301; Ganong's Review of Medical Physiology, 22nd Edition, Page 393.
Thyroid gland
Parathyroid gland
Adrenal glands
Ovaries