This FlowCytomix Simplex Kit is designed for the measurement of human Calcitonin in an immunoassay analyzed on a flow cytometer. Together with the FlowCytomix Human Basic Kit (cat. BMS8420FF), this kit can be used to detect Calcitonin alone or can be multiplexed with other Simplex Kits to measure a variety of analytes. This kit contains bead population A9. Calcitonin is a 32-amino acid linear polypeptide hormone that is produced in humans primarily by parafollicular cells (also known as C-cells) of the thyroid, and in many other animals. Calcitonin is synthesized as a 136 amino acid precursor molecule, which is processed by proteolytic cleavage and by amidation of the carboxy terminal proline residue prior to secretion. The same gene transcript encodes calcitonin and a-calcitonin gene-related peptide (a-CGRP). Both are integrated into the calcitonin family of peptides and generated by cell specific alternative splicing. Calcitonin binds to its receptor expressed in mature osteoclasts and cells in the distal nephron. The inhibition of bone resorption and a decrease in calcium tubular resorption results in lower serum calcium, opposing the effects of parathyroid hormone (PTH). Calcitonin and PTH are complementary hormones involved in the acquisition and maintenance of bone mass and regulation of calcium metabolism. Calcitonin may primarily protect the skeleton during phases of calcium stress, such as growth, pregnancy, and lactation. Calcitonin is approved as medication for osteoporosis. A chronic deficiency of calcitonin is found in patients with thyroid dysgenesis. Increased serum levels are a feature of medullary thyroid carcinoma. Measurement of soluble calcitonin in serum is more sensitive than cytology in the diagnosis of medullary thyroid carcinoma. Furthermore, calcitonin is also increased in serum of patients with primary lung cancer or Hashimoto’s thyroiditis. In rare cases, pancreatic endocrine tumors have also been observed to secrete calcitonin. Those are often malignant and indicate a poor prognosis.