{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"Calcitonin is a 32-amino acid polypeptide hormone that is produced in humans primarily by C-cells located in the thyroid. It acts to reduce blood calcium (Ca2+), opposing the effects of parathyroid hormone (PTH). Calcitonin can also protect the skeleton from excessive loss of bone during periods of high calcium demand, such as lactation. Immunohistochemical staining with calcitonin antibodies has proven to be an effective way of demonstrating the existence of calcitonin-producing cells in the thyroid and aid in the studies of a wide spectrum of C-cell proliferative abnormalities."}]}]}