72203-93-1

Calcitetrol(1α, 24, 25-Trihydroxy VD3) is the hormonally active form of vitamin D with three hydroxyl groups. IC50 value: Target: Calcitriol increases blood calcium levels ([Ca2+]) by promoting absorption of dietary calcium from the gastrointestinal tract and increasing renal tubular reabsorption of calcium, thus reducing the loss of calcium in the urine. Calcitriol also stimulates release of calcium from bone by its action on the specific type of bone cells referred to as osteoblasts, causing them to release RANKL, which in turn activates osteoclasts.

[1] Akiyoshi-Shibata M, et al. Further oxidation of hydroxycalcidiol by calcidiol 24-hydroxylase. A study with the mature enzyme expressed in Escherichia coli. Eur J Biochem. 1994 Sep 1;224(2):335-43. DOI:10.1111/j.1432-1033.1994.00335.x