Cholecalciferol must be regarded as a pro-hormone rather than a vitamin, since it is normally produced in skin under the influence of ultraviolet light. Cholecalciferol must be metabolized in liver to 25-hydroxycholecalciferol and subsequently to 1,25-dihydroxycholecalciferol before it can act on intestine, bone and kidney to provide calcium and phosphorus for bone mineralization and neuromuscu...

The active vitamin D metabolites 1 alpha, 25-dihydroxycholecalciferol (Rocaltrol) and the analogue 1 alpha-hydroxycholecalciferol (One-Alpha) are adequately absorbed after oral administration in the preterm infant. The absorption pattern is similar to that seen in adults.

Rats raised from weaning on regiments adequate in calcium and phosphorus but deficient in vitamin D will have no detectable intestinal calcium-binding proteins (CaBP), whether or not they show other signs of vitamin D deficiency, such as hypocalcemia. When hypocalcemic, vitamin D-deficient animals were treated with 25-hydroxycholecalciferol, a vitamin D metabolite, they showed a dose-dependent ...

'Transcalciferin' (the serum transport protein for cholecalciferol and related substances) of two New World monkeys, Cebus apella and Cebus albifrons, was found to be immunologically identical with the transcalciferin of other monkeys and partially with that ofman. In contrast with the a-globulin mobility of the transcalciferin of other primates, the transcalciferin of cebus monkey has the elec...

The effect of high doses of 25-hydroxycholecalciferol on plasma calcium concentration was studied in rats receiving a low-calcium normal vitamin D diet. In bilaterally nephrectomized animals, as in sham-operated controls, 62.5 nmol of 25-hyroxycholecalciferol did not produce a rise of plasma calcium concentration. In contrast, the administration of 125 or 625 nmol, doses 1,000-5,000 times the m...

The effects of providing ultraviolet (uv) radiation (285 to 315 nm, ultraviolet B) on calcium metabolism in two groups of 20 healthy grey parrots (Psittacus e erithacus) fed either a seed or pellet-based diet were investigated. There was a significant increase in the concentration of ionised calcium in the plasma of both groups, independent of the calcium and vitamin D(3) content of the diets f...

This study aims to evaluate the vitamin D receptor (VDR) expression and intracellular amounts of VDRs in CD4+ CD8+ lymphocytes renal transplant (RT) recipients with chronic allograft dysfunction (CAD). A total 43 patients (Group 1:RT patients=29 patients, 15 CAD proven by biopsy 1a), 14 stable function 1b), Group 2:Control group=14 healthy individuals) have been enrolled this study. 25-hydroxyc...