Calcitonin

  • Calcitonin is a hypocalcemic peptide hormone that in several mammalian species acts as an antagonist to PTH. The hypocalcemic activity of calcitonin is accounted for primarily by inhibition of osteoclast-mediated bone resorption and secondarily by stimulation of renal calcium clearance..
  • The ultimobranchial body arises from bilateral ventral swellings of the 4th pharyngeal pouches and gets integrated into the thyroid where it forms the parafollicular cells or C-cells for the production of calcitonin.
  • Medullary thyroid carcinoma is classically associated with calcitonin induced amyloid deposition.
  • Calcitonin (CT) is the main medullary thyroid carcinoma (MTC) tumor marker.Screening method for medullary carcinoma thyroid is Serum Calcitonin.
  • Procalcitonin (PCT), the prohormone of calcitonin, is free of these limitations but is currently used only as a sepsis marker.
  • Calcitonin is secreted by Thyroid Gland.
  • Calcitonin lowers circulating calcium and phosphate levels. It exerts its calcium-lowering effect by inhibiting bone resorption by direct action on Osteoclasts.
  • The ability of calcitonin to block bone resorption and lower serum calcium makes it a useful drug for the treatment of Paget's disease, hypercalcemia, and osteoporosis.
  • Salmon calcitonin is approved for clinical use. The latter product also is available as a nasal spray, introduced for once-daily treatment of postmenopausal osteoporosis.
  • For Paget's disease, calcitonin generally is administered by subcutaneous injection because intranasal delivery is relatively ineffective owing to limited bioavailability.
  • Intranasal calcitonin is given for a 65 year old post-menopausal lady. Osteoporosis is the likely indication.
  • Hormones that stimulate Adenylyl Cyclase and the production of cAMP: Acetylcholine, ADH ,Beta -Adrenergics ,Calcitonin, CRH ,FSH, Glucagon, hCG ,LH ,LPH ,MSH, PTH ,TSH.
  • Hormones that inhibit Adenylyl Cyclase and the production of cAMP: Acetylcholine, Alpha 2-Adrenergics, Angiotensin II, Somatostatin.
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