calcitriol

(noun)

the active metabolite 1,25-dihydroxycholecalciferol of vitamin D3 that is involved in the absorption of calcium

Related Terms

Examples of calcitriol in the following topics:

  • Intracellular Hormone Receptors

    • For example, the active vitamin D metabolite, calcitriol, mediates its biological effects by binding to the vitamin D receptor (VDR), which is principally located in the nuclei of target cells.
    • The binding of calcitriol to the VDR allows the VDR to act as a transcription factor that modulates the gene expression of transport proteins that are involved in calcium absorption in the intestine.

  • Organs with Secondary Endocrine Functions

    • The kidneys also release calcitriol, which aids in the absorption of calcium (Ca2+) and phosphate ions.

  • Hormonal Control of Blood Calcium Levels

    • PTH triggers the formation of calcitriol, an active form of vitamin D, which acts on the intestines to increase absorption of dietary calcium.

  • Parathyroid Glands

    • Finally, PTH stimulates synthesis and secretion of calcitriol by the kidneys, which enhances Ca2+ absorption by the digestive system.