Vitamin D receptors have been isolated in brain, prostate, breast, colon, heart and immune cells and these cells respond directly to 1,25-dihydroxyvitamin D.
Vitamin D status is measured by 25-hydroxyvitamin D, as levels of 1,25-dihydroxyvitamin D in deficiency states may be normal, high or low.
His 1,25-dihydroxyvitamin D
(calcitriol) level was normal at 23 pg/mL (normal, 15-60 pg/mL).
And make sure that your doctor orders a test for 25-hydroxyvitamin D, not 1,25-dihydroxyvitamin D
, which is the active form.
receptor in bovine thymus gland.
Intact parathyroid hormone (PTH) and 1,25-dihydroxyvitamin D
in plasma were determined respectively by an IRMA and a radioreceptor assay (both from Nichols Institute).
We prospectively examined the relationship between plasma levels of 25-hydroxyvitamin D [25(OH)D] and 1,25-dihydroxyvitamin D
[1,25(OH)2D] and risk of breast cancer in a case-control study nested within the Nurses' Health Study cohort.