Calcitonin

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Last update: Wednesday, 08 Nov 2023 at 11.27 pm.

The structure of calcitonin

Calcitonin, (thyrocalcitonin, CT), is a peptide hormone produced by the parafollicular (C-cells) of the thyroid gland. Its concentration increases with hypercalcemia. It lowers the level calcium ions in the blood and thus represents an antagonist to the parathormonu produced by the main cells of the parathyroid bodies. Parathormon and calcitonin stimulate reabsorption in the ascending part of the loop of Henle, where calcium is reabsorbed transcellularly and paracellularly [1] Parathormone reduces the resulting concentration of calcium in the urine, calcitonin increases it. In the distal part of the nephron, in addition to parathyroid hormone and calcitonin, calcitriol also participates in reabsorption of calcium.

Calcitonin:


Effects of calcitonin

    • Bone: retains Ca + P
    • kidney: reduces reabsorption of Ca + P
    • intestine - no direct effect (calcitonin most likely reduces the formation of calcitriol in the kidneys).[2]

Benchmarks

men, normal laboratory value: 3-26 ng/l women, normal laboratory value: 2-17 ng/l

The regulation of calcium in the organism

Parathormon Calcitonine Vitamin D [2]
bone osteoclast activation,

calcemia and phosphatemia rise

inhibition of osteoclasts,

deposition of Ca 2+ in bones

skeletal mineralization;

high levels, on the other hand, decalcify

kidneyx stimulates Ca 2+ resorption, inhibits phosphate resorption,

stimulates vitamin D synthesis

increases the excretion of Ca 2+ ,

increases the excretion of phosphates

increases the reabsorption of Ca 2+ and phosphates
intestine stimulates resorption of Ca 2+ and phosphates – stimulates resorption of Ca 2+ and phosphates

References

  1. ↑ WILHELM, Z. Co je dobré vědět o vápník. Praktické lékárenství [online]. 2007, y. -, p. 184-189, Available from <http://solen.cz/pdfs/lek/2007/04/09.pdf>. 
  2. ↑ a b SILBERNAGL, Stefan – DESPOPOULOS, Agamemnon. Atlas fyziologie člověka :  6. vydání, zcela přepracované a rozšířené. 3. edition. Praha : Grada, 2004. pp. 290-293. ISBN 80-247-0630-X. Cite error: Invalid <ref> tag; name "silbernagl" defined multiple times with different content

References

  • VÁCLAVA, Václava – VAJNER, Luděk. Funkční histologie. 1. edition. Jinočany : H & H, 2000. ISBN 80-86022-80-3.
  • VOKURKA, Martin – HUGO, Jan. Velký lékařský slovník. 9. edition. Praha : Maxdorf, 2009. 1159 pp. ISBN 978-80-7345-202-5.