Calcitonin is a 32-amino acid linear polypeptide hormone A hormone is a chemical released by a cell in one part of the body, that sends out messages that affect cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. It is essentially a chemical messenger that transports a signal from one cell to another. All multicellular organisms produce hormones; that is produced in humans Humans are a species of animal known taxonomically as Homo sapiens , and are the only extant member of the Homo genus of bipedal primates in Hominidae, the great ape family. However, in some cases "human" is used to refer to any member of the genus Homo primarily by the parafollicular Parafollicular cells are cells in the thyroid that produce and secrete calcitonin. They are located adjacent to the thyroid follicles and reside in the connective tissue. These cells are large and have a pale stain compared with the follicular cells or colloid cells (also known as C-cells) of the thyroid In vertebrate anatomy, the thyroid gland or simply, the thyroid, is one of the largest endocrine glands in the body, and is not to be confused with the "parathyroid glands" . The thyroid gland is found in the neck, inferior to (below) the thyroid cartilage (also known as the 'Adam's Apple') and at approximately the same level as the, and in many other animals in the ultimobranchial body.^[2] It acts to reduce blood calcium Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth most abundant element by mass in the Earth's crust. Calcium is also the fifth most abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride, (Ca²⁺), opposing the effects of parathyroid hormone Parathyroid hormone , parathormone or parathyrin, is secreted by the parathyroid glands as a polypeptide containing 84 amino acids. It acts to increase the concentration of calcium (Ca2+) in the blood, whereas calcitonin (a hormone produced by the parafollicular cells (C cells) of the thyroid gland) acts to decrease calcium concentration. PTH acts (PTH).^[3] It has been found in fish A fish is any aquatic vertebrate animal that is covered with scales, and equipped with two sets of paired fins and several unpaired fins. Most fish are "cold-blooded", or ectothermic, allowing their body temperatures to vary as ambient temperatures change. Fish are abundant in most bodies of water. They can be found in nearly all aquatic, reptiles Reptiles are animals in the class Reptilia characterized by breathing air, a "cold-blooded" (poikilothermic) metabolism, laying tough-shelled amniotic eggs (or retaining the same membrane system in species with live birth), and skin with scales or scutes. They are tetrapods (either having four limbs or being descended from four-limbed, birds Birds are winged, bipedal, endothermic (warm-blooded), egg-laying, vertebrate animals. There are around 10,000 living species, making them the most varied of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from the 5 cm (2 in) Bee Hummingbird to the 2.75 m (9 ft) Ostrich, and mammals Mammals are a class of vertebrate, air-breathing animals whose females are characterized by the possession of mammary glands while both males and females are characterized by hair and/or fur, three middle ear bones used in hearing, and a neocortex region in the brain. Some mammals have sweat glands, but most do not. Its importance in humans has not been as well established as its importance in other animals, as its function is usually not significant in the regulation of normal calcium homeostasis.^[4]

Biosynthesis

Calcitonin is formed by the proteolytic Proteolysis is the directed degradation of proteins by cellular enzymes called proteases or by intramolecular digestion cleavage of a larger prepropeptide, which is the product of the CALC1 gene (CALCA). The CALC1 gene belongs to a superfamily of related protein hormone precursors including islet amyloid precursor protein, calcitonin gene-related peptide Calcitonin gene related peptide is a member of the calcitonin family of peptides, which in humans exists in two forms, α-CGRP and β-CGRP. α-CGRP is a 37 amino acid peptide and is formed from the alternative splicing of the calcitonin/CGRP gene located on chromosome 11. CGRP is one of the most abundant peptides produced in both peripheral and, and the precursor of adrenomedullin.

Physiology

The hormone participates in calcium Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth most abundant element by mass in the Earth's crust. Calcium is also the fifth most abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride, (Ca²⁺) and phosphorus Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus is commonly found in inorganic phosphate rocks. Elemental phosphorus exists in two major forms – white phosphorus and red phosphorus. Although the term "phosphorescence", meaning glow after metabolism Metabolism is the set of chemical reactions that happen in living organisms to maintain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories. Catabolism breaks down organic matter, for example to harvest energy in cellular. In many ways, calcitonin counteracts parathyroid hormone Parathyroid hormone , parathormone or parathyrin, is secreted by the parathyroid glands as a polypeptide containing 84 amino acids. It acts to increase the concentration of calcium (Ca2+) in the blood, whereas calcitonin (a hormone produced by the parafollicular cells (C cells) of the thyroid gland) acts to decrease calcium concentration. PTH acts (PTH).

To be specific, calcitonin affects blood Ca²⁺ levels in four ways:

• Inhibits Ca²⁺ absorption by the intestines In human anatomy, the intestine is the segment of the alimentary canal extending from the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine. In humans, the small intestine is further subdivided into the duodenum, jejunum and ileum while the large intestine is subdivided into^[5]
• Inhibits osteoclast An osteoclast (from the Greek words for "bone" and "broken" (κλαστός)) is a type of bone cell that removes bone tissue by removing its mineralized matrix and breaking up the organic bone (organic dry weight is 90% collagen). This process is known as bone resorption. Osteoclasts and osteoblasts are instrumental in activity in bones Bones are rigid organs that form part of the endoskeleton of vertebrates. They function to move, support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue. Because bones come in a variety of shapes and have a complex internal and external structure^[6]
• Inhibits phosphate reabsorption by the kidney The kidneys are paired organs with several functions. They are seen in many types of animals, including vertebrates and some invertebrates. They are an essential part of the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid-base balance, and regulation of blood pressure. They serve the tubules^[7]
• Calcitonin inhibits tubular reabsorption of Ca²⁺, leading to increased rates of its loss in urine..^[7]

Secretion of calcitonin is stimulated by:

• an increase in serum [Ca²⁺]^[8]
• gastrin In humans, gastrin is a hormone that stimulates secretion of gastric acid by the parietal cells of the stomach and aids in gastric motility. It is released by G cells in the stomach, duodenum, and the pancreas. Its release is stimulated by gastric luminal peptides. Its existence was first suggested in 1905 by the British physiologist John Sydney and pentagastrin.^[9]

Actions

Its actions, in a broad sense, are:

• Bone mineral metabolism:

- Protect against Ca²⁺ loss from skeleton during periods of Ca²⁺ stress such as pregnancy Pregnancy is the carrying of one or more offspring, known as a fetus or embryo, inside the womb of a female. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets. Human pregnancy is the most studied of all mammalian pregnancies. Childbirth usually occurs about 38 weeks after conception; i.e., approximately 40 weeks and lactation Lactation describes the secretion of milk from the mammary glands, the process of providing that milk to the young, and the period of time that a mother lactates to feed her young. The process occurs in all female mammals, and in humans it is commonly referred to as breastfeeding or nursing. In most species milk comes out of the mother's nipples;

• Serum calcium Calcium metabolism or calcium homeostasis is the mechanism by which the body maintains adequate calcium levels. Derangements of this mechanism lead to hypercalcemia or hypocalcemia, which both can have important consequences for health level regulation

- Prevent postprandial hypercalcemia Hypercalcaemia is an elevated calcium level in the blood. (Normal range: 9-10.5 mg/dL or 2.2-2.6 mmol/L). It can be an asymptomatic laboratory finding, but because an elevated calcium level is often indicative of other diseases, a diagnosis should be undertaken if it persists. It can be due to excessive skeletal calcium release, increased resulting from absorption of Ca²⁺ from foods during a meal

- Vitamin D Vitamin D is a group of fat-soluble secosteroids, the two major physiologically relevant forms of which are vitamin D2 and vitamin D3 (cholecalciferol). Vitamin D without a subscript refers to either D2 or D3 or both. Vitamin D3 is produced in the skin of vertebrates after exposure to ultraviolet B light from the sun or artificial sources, and regulation

• A satiety Eating is the ingestion of food to provide for all humans and animals nutritional needs, particularly for energy and growth. Animals and other heterotrophs must eat in order to survive: carnivores eat other animals, herbivores eat plants, and omnivores consume a mixture of both. Eating is an activity of daily living hormone:

- Inhibit food intake in rats and monkeys

- May have CNS The central nervous system is the part of the nervous system that coordinates the activity of all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish. It contains the majority of the nervous system and consists of the brain and the spinal cord, as well as action involving the regulation of feeding and appetite

Receptor

The calcitonin receptor The calcitonin receptor is a G protein-coupled receptor that binds the peptide hormone calcitonin and is involved in maintenance of calcium homeostasis, particularly with respect to bone formation and metabolism, found primarily on osteoclasts^[10], is a G protein-coupled receptor G protein-coupled receptors , also known as seven-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptor, and G protein-linked receptors (GPLR), comprise a large protein family of transmembrane receptors that sense molecules outside the cell and activate inside signal transduction pathways and, ultimately,, which is coupled by G_s to adenylyl cyclase Adenylate cyclase is a lyase enzyme. It is a part of the cAMP-dependent pathway and thereby to the generation of cAMP Cyclic adenosine monophosphate is a second messenger important in many biological processes. cAMP is derived from adenosine triphosphate (ATP) and used for intracellular signal transduction in many different organisms, conveying the cAMP-dependent pathway in target cells. It also affect the ovaries in women and the testes in men.

Discovery

Calcitonin was purified in 1962 by Copp and Cheney.^[11] While it was initially considered a secretion of the parathyroid glands The parathyroid glands are small endocrine glands in the neck that produce parathyroid hormone. Humans have four parathyroid glands, which are usually located behind the thyroid gland, and, in rare cases, within the thyroid gland or in the chest. Parathyroid glands control the amount of calcium in the blood and within the bones, it was later identified as the secretion of the C-cells Parafollicular cells are cells in the thyroid that produce and secrete calcitonin. They are located adjacent to the thyroid follicles and reside in the connective tissue. These cells are large and have a pale stain compared with the follicular cells or colloid of the thyroid In vertebrate anatomy, the thyroid gland or simply, the thyroid, is one of the largest endocrine glands in the body, and is not to be confused with the "parathyroid glands" . The thyroid gland is found in the neck, inferior to (below) the thyroid cartilage (also known as the 'Adam's Apple') and at approximately the same level as the gland.^[12]

Pharmacology

Salmon calcitonin is used for the treatment of:

• Postmenopausal osteoporosis Osteoporosis is a disease of bones that leads to an increased risk of fracture. In osteoporosis the bone mineral density is reduced, bone microarchitecture is disrupted, and the amount and variety of proteins in bone is altered. Osteoporosis is defined by the World Health Organization (WHO) in women as a bone mineral density 2.5 standard
• Hypercalcaemia Hypercalcaemia is an elevated calcium level in the blood. (Normal range: 9-10.5 mg/dL or 2.2-2.6 mmol/L). It can be an asymptomatic laboratory finding, but because an elevated calcium level is often indicative of other diseases, a diagnosis should be undertaken if it persists. It can be due to excessive skeletal calcium release, increased
• Paget's disease
• Bone metastases
• Phantom limb pain^[13]

It has been investigated as a possible non-operative treatment for spinal stenosis Spinal stenosis is a medical condition in which the spinal canal narrows and compresses the spinal cord and nerves. This is usually due to the common occurrence of spinal degeneration that occurs with aging. It can also sometimes be caused by spinal disc herniation, osteoporosis or a tumor. In the cervical and lumbar (low back) region it can be a.

The following information is from the UK Electronic Medicines Compendium^[14]

General characteristics of the active substance

Salmon calcitonin is rapidly absorbed and eliminated. Peak plasma concentrations are attained within the first hour of administration.

Animal studies have shown that calcitonin is primarily metabolised via proteolysis in the kidney following parenteral administration. The metabolites lack the specific biological activity of calcitonin. Bioavailability following subcutaneous and intramuscular injection in humans is high and similar for the two routes of administration (71% and 66%, respectively).

Calcitonin has short absorption and elimination half-lives of 10-15 minutes and 50-80 minutes, respectively. Salmon calcitonin is primarily and almost exclusively degraded in the kidneys, forming pharmacologically-inactive fragments of the molecule. Therefore, the metabolic clearance is much lower in patients with end-stage renal failure than in healthy subjects. However, the clinical relevance of this finding is not known. Plasma protein binding is 30% to 40%.

Characteristics in patients

There is a relationship between the subcutaneous dose of calcitonin and peak plasma concentrations. Following parenteral administration of 100 IU calcitonin, peak plasma concentration lies between about 200 and 400 pg/ml. Higher blood levels may be associated with increased incidence of nausea and vomiting.

Preclinical safety data

Conventional long-term toxicity, reproduction, mutagenicity, and carcinogenicity studies have been performed in laboratory animals. Salmon calcitonin is devoid of embryotoxic, teratogenic, and mutagenic potential.

An increased incidence of pituitary adenomas has been reported in rats given synthetic salmon calcitonin for 1 year. This is considered a species-specific effect and of no clinical relevance. Salmon calcitonin does not cross the placental barrier.

In lactating animals given calcitonin, suppression of milk production has been observed. Calcitonin is secreted into the milk.

Pharmaceutical manufacture

Calcitonin was extracted from the Ultimobranchial glands (thyroid-like glands) of fish, particularly salmon. Salmon calcitonin resembles human calcitonin, but is more active. At present, it is produced either by recombinant DNA Recombinant DNA is a form of DNA that does not exist naturally, but is created by combining DNA sequences that would not normally occur together. In terms of genetic modification, recombinant DNA is introduced through the addition of relevant DNA into an existing organismal DNA, such as the plasmids of bacteria, to code for or alter different technology or by chemical peptide synthesis In organic chemistry, peptide synthesis is the production of peptides, which are organic compounds in which multiple amino acids are linked via peptide bonds which are also known as amide bonds. The biological process of producing long peptides is known as protein biosynthesis. The pharmacological properties of the synthetic and recombinant peptides have been demonstrated to be qualitatively and quantitatively equivalent.^[14]

Uses of calcitonin

Treatments

Calcitonin can be used therapeutically for the treatment of hypercalcemia Hypercalcaemia is an elevated calcium level in the blood. (Normal range: 9-10.5 mg/dL or 2.2-2.6 mmol/L). It can be an asymptomatic laboratory finding, but because an elevated calcium level is often indicative of other diseases, a diagnosis should be undertaken if it persists. It can be due to excessive skeletal calcium release, increased or osteoporosis Osteoporosis is a disease of bones that leads to an increased risk of fracture. In osteoporosis the bone mineral density is reduced, bone microarchitecture is disrupted, and the amount and variety of proteins in bone is altered. Osteoporosis is defined by the World Health Organization (WHO) in women as a bone mineral density 2.5 standard.

Oral calcitonin may have a chondroprotective role in osteoarthritis (OA), according to data in rats presented in December, 2005, at the 10th World Congress of the Osteoarthritis Research Society International (OARSI) in Boston, Massachusetts. Although calcitonin is a known antiresorptive agent, its disease-modifying effects on chondrocytes and cartilage metabolisms have not been well established until now.

This new study, however, may help to explain how calcitonin affects osteoarthritis. “Calcitonin acts both directly on osteoclasts, resulting in inhibition of bone resorption and following attenuation of subchondral bone The epiphysis is the rounded end of a long bone, at its joint with adjacent bone. Between the epiphysis and diaphysis (the long midsection of the long bone) lies the metaphysis, including the epiphyseal plate (growth plate). At the joint, the epiphysis is covered with articular cartilage; below that covering is a zone similar to the epiphyseal turnover, and directly on chondrocytes, attenuating cartilage degradation and stimulating cartilage formation,” says researcher Morten Karsdal, MSC, PhD, of the department of pharmacology at Nordic Bioscience in Herlev, Denmark. “Therefore, calcitonin may be a future efficacious drug for OA.”^[15]

Subcutaneous injections of calcitonin in patients suffering from mania Mania, the presence of which is a criterion for certain psychiatric diagnoses, is a state of abnormally elevated or irritable mood, arousal, and/ or energy levels. The word derives from the Greek "μανία" , "madness, frenzy" and that from the verb "μαίνομαι" (mainomai), "to be mad, to rage, to be resulted in significant decreases in irritability, euphoria and hyperactivity and hence calcitonin holds promise for treating bipolar disorder Bipolar disorder or manic–depressive disorder is a psychiatric diagnosis that describes a category of mood disorders defined by the presence of one or more episodes of abnormally elevated energy levels, cognition, and mood and one or more depressive episodes. The elevated moods are clinically referred to as mania or, if milder, hypomania.^[16] However no further work on this potential application of calcitonin has been reported.

Diagnostics

It may be used diagnostically as a tumor marker A tumor marker is a substance found in the blood, urine, or body tissues that can be elevated in cancer, among other tissue types. There are many different tumor markers, each indicative of a particular disease process, and they are used in oncology to help detect the presence of cancer. An elevated level of a tumor marker can indicate cancer; for a form of thyroid cancer Thyroid cancer is a thyroid neoplasm that is malignant. It can be treated with radioactive iodine or surgical resection of the thyroid gland. Chemotherapy or radiotherapy may also be used (medullary thyroid adenocarcinoma), in which high calcitonin levels may be present and elevated levels after surgery may indicate recurrence. It may even be used on biopsy A biopsy is a medical test involving the removal of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease. The tissue is generally examined under a microscope by a pathologist, and can also be analyzed chemically. When an entire lump or suspicious area is samples from suspicious lesions (e.g., swollen lymph nodes A lymph node is a small circular ball shape organ of the immune system, distributed widely throughout the body and linked by lymphatic vessels. Lymph nodes are garrisons of B, T, and other immune cells. Lymph nodes are found all through the body, and act as filters or traps for foreign particles. They contain white blood cells that use oxygen to) to establish whether they are metastasis Metastasis , or metastatic disease (sometimes abbreviated mets), is the spread of a disease from one organ or part to another non-adjacent organ or part. It had been previously thought that only malignant tumor cells and infections have the capacity to metastasize; however, this is being reconsidered due to new research of the original cancer.

Structure

Calcitonin is a polypeptide hormone of 32 amino acids, with a molecular weight of 3454.93 daltons. Its structure comprises a single alpha helix.^[1] Alternative splicing of the gene coding for calcitonin produces a distantly related peptide of 37 amino acids, called calcitonin gene-related peptide (CGRP), beta type.^[17]

The following are the amino acid sequences of salmon and human calcitonin:^[18]

• salmon: Cys-Ser-Asn-Leu-Ser-Thr-Cys-Val-Leu-Gly-Lys-Leu-Ser-Gln-Glu-Leu-His-Lys-Leu-Gln-Thr-Tyr-Pro-Arg-Thr-Asn-Thr-Gly-Ser-Gly-Thr-Pro
• human: Cys-Gly-Asn-Leu-Ser-Thr-Cys-Met-Leu-Gly-Thr-Tyr-Thr-Gln-Asp-Phe-Asn-Lys-Phe-His-Thr-Phe-Pro-Gln-Thr-Ala-Ile-Gly-Val-Gly-Ala-Pro

Compared to salmon calcitonin, human calcitonin differs at 16 residues.

See also

• Procalcitonin

References

1. ^ ^{a b} PDB 2glhAndreotti G, Méndez BL, Amodeo P, Morelli MA, Nakamuta H, Motta A (August 2006). "Structural determinants of salmon calcitonin bioactivity: the role of the Leu-based amphipathic alpha-helix". J. Biol. Chem. 281 (34): 24193–203. doi:10.1074/jbc.M603528200. PMID 16766525.
2. ^ Costoff A. "Sect. 5, Ch. 6: Anatomy, Structure, and Synthesis of Calcitonin (CT)". Endocrinology: hormonal control of calcium and phosphate. Medical College of Georgia. http://www.lib.mcg.edu/edu/eshuphysio/program/section5/5ch6/s5ch6_21.htm. Retrieved 2008-08-07.
3. ^ Boron WF, Boulpaep EL (2004). "Endocrine system chapter". Medical Physiology: A Cellular And Molecular Approach. Elsevier/Saunders. ISBN 1-4160-2328-3.
4. ^ Costoff A. "Sect. 5, Ch. 6: Biological Actions of CT". Medical College of Georgia. http://www.lib.mcg.edu/edu/eshuphysio/program/section5/5ch6/s5ch6_23.htm. Retrieved 2008-08-07.
5. ^ Costoff A. "Sect. 5, Ch. 6: Effects of CT on the Small Intestine". Medical College of Georgia. http://www.lib.mcg.edu/edu/eshuphysio/program/section5/5ch6/s5ch6_26.htm. Retrieved 2008-08-07.
6. ^ Costoff A. "Sect. 5, Ch. 6: Effects of CT on Bone". Medical College of Georgia. http://www.lib.mcg.edu/edu/eshuphysio/program/section5/5ch6/s5ch6_24.htm. Retrieved 2008-08-07.
7. ^ ^{a b} Carney SL (1997). "Calcitonin and human renal calcium and electrolyte transport". Miner Electrolyte Metab 23 (1): 43–7. PMID 9058369.
8. ^ Costanzo, Linda S. (2007). BRS Physiology. Lippincott, Williams, & Wilkins. pp. 263. ISBN 978-0781773119. http://www.amazon.com/Physiology-Board-Review-Linda-Costanzo/dp/0781773113/.
9. ^ Erdogan MF, Gursoy A, Kulaksizoglu M (October 2006). "Long-term effects of elevated gastrin levels on calcitonin secretion". J Endocrinol Invest. 29 (9): 771–775. PMID 17114906. http://www.kurtis.it/abs/index.cfm?id_articolo_numero=3037.
10. ^ Nicholson GC, Moseley JM, Sexton PM, et al (1986). "Abundant calcitonin receptors in isolated rat osteoclasts. Biochemical and autoradiographic characterization". J Clin Invest 78 (2): 355–60. doi:10.1172/JCI112584. PMID 3016026.
11. ^ Copp DH, Cheney B (January 1962). "Calcitonin-a hormone from the parathyroid which lowers the calcium-level of the blood". Nature 193: 381–2. doi:10.1038/193381a0. PMID 13881213.
12. ^ Hirsch PF, Gauthier GF, Munson PL (august 1963). "Thyroid hypocalcemic principle and recurrent laryngeal nerve injury as factors affecting the response to parathyroidectomy in rats". Endocrinology 73: 244–252. doi:10.1210/endo-73-2-244. PMID 14076205.
13. ^ Wall GC, Heyneman CA (April 1999). "Calcitonin in phantom limb pain". Ann Pharmacother 33 (4): 499–501. doi:10.1345/aph.18204. PMID 10332543.
14. ^ ^{a b} "Electronic Medicines Compendium". http://emc.medicines.org.uk/. Retrieved 2008-08-07.
15. ^ Kleinman DM (2006-01-04). "Oral Calcitonin May Delay Onset of Joint Disease and Relieve Pain of OA". Musculoskeletal Report. Musculoskeletal Report, LLC. http://www.mskreport.com/articles.cfm?ArticleID=515. Retrieved 2008-08-07.
16. ^ Vik A, Yatham LN (March 1998). "Calcitonin and bipolar disorder: a hypothesis revisited". J Psychiatry Neurosci 23 (2): 109–17. PMID 9549251.
17. ^ "calcitonin domain annotation". SMART (a Simple Modular Architecture Research Tool). embl-heidelberg.de. http://smart.embl-heidelberg.de/smart/do_annotation.pl?BLAST=DUMMY&DOMAIN=SM00113. Retrieved 2009-02-22.
18. ^ http://www.newworldencyclopedia.org/entry/Calcitonin

Further reading

• MacIntyre I, Alevizaki M, Bevis PJ, Zaidi M (1987). "Calcitonin and the peptides from the calcitonin gene". Clin. Orthop. Relat. Res. &na; (217): 45–55. doi:10.1097/00003086-198704000-00007. PMID 3549095.
• Di Angelantonio S, Giniatullin R, Costa V, et al. (2004). "Modulation of neuronal nicotinic receptor function by the neuropeptides CGRP and substance P on autonomic nerve cells". Br. J. Pharmacol. 139 (6): 1061–73. doi:10.1038/sj.bjp.0705337. PMID 12871824.
• Findlay DM, Sexton PM (2005). "Calcitonin". Growth Factors 22 (4): 217–24. doi:10.1080/08977190410001728033. PMID 15621724.
• Sponholz C, Sakr Y, Reinhart K, Brunkhorst F (2007). "Diagnostic value and prognostic implications of serum procalcitonin after cardiac surgery: a systematic review of the literature". Critical care (London, England) 10 (5): R145. doi:10.1186/cc5067. PMID 17038199.
• Schneider HG, Lam QT (2007). "Procalcitonin for the clinical laboratory: a review". Pathology 39 (4): 383–90. doi:10.1080/00313020701444564. PMID 17676478.

External links

• The Calcitonin Protein
• MeSH Calcitonin

Categories: Human proteins | Peptide hormones | Hormones of the thyroid gland | Human hormones | Hormones of calcium metabolism

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