vitamin D is 25-hydroxylated in the liver, before being activated by 1alpha-hydroxylation in the kidney. Recently, the rat cytochrome P450 2J3 (CYP2J3) has been identified as a principal vitamin D 25-hydroxylase in the rat [Yamasaki T, Izumi S, Ide H, Ohyama Y. Identification of a novel rat microsomal vitamin D3 25-hydroxylase. J Biol Chem 2004;279(22):22848-56]. In this study, we examine wheth...

In all species tested, except humans, biological differences between vitamins D2 and D3 are accepted as fact. To test the presumption of equivalence in humans, we compared the ability of equal molar quantities of vitamin D2 or D3 to increase serum 25-hydroxyvitamin D [25(OH)D], the measure of vitamin D nutrition. Subjects took 260 nmol (approximately 4000 IU) vitamin D2 (n=17) or vitamin D3 (n=...

One-day-old chicks were depleted of vitamin D. At 3 weeks their right tibiae, and those of a control group given vitamin D3, were fractured and pinned. After fracture the controls were kept on vitamin D3. Another group was left vitamin D-deficient. The remaining depleted chicks, divided into four groups, were given vitamin D3, 24,25-dihydroxyvitamin D3 [24,25(OH)2D3], 1,25-dihydroxyvitamin D3 [...

There have been methodological problems for studying hypovitaminosis D and K in the elderly. First, studies were done either by evaluating food intake or measuring their circulating levels, but rarely by both in Japan. In this paper, vitamin D and K intakes and their circulating levels were simultaneously determined. Second issue is whether hypovitaminosis D and K are independent of general mal...

An experiment was conducted to elucidate the effect of graded levels of vitamin D3 in White Leghorn (WL) layer breeders on egg production, shell quality, hatchability of eggs and juvenile performance of offspring during their late laying period (7288 wk). White Leghorn breeder females were randomly divided into 5 groups of 50 each and were housed in individual California cages in an open-side h...

OBJECTIVE Supplementing lactating mothers with high doses of vitamin D3 can adequately meet vitamin D requirements of the breastfed infant. We compared the effect of bolus versus daily vitamin D3 dosing in lactating mothers on vitamin D3 catabolism. We hypothesized that catabolism of 25(OH)D3 to 24,25(OH)2D3 would be greater in the bolus than in the daily dose group. DESIGN, SETTING AND PATIE...

We aim to evaluate whether calcium and vitamin D intake is associated with 25-hydroxyvitamin D (25-OH-Vitamin D3) and parathyroid hormone (PTH) serum concentrations or is associated with either the phalangeal dual energy X-ray absorptiometry (pDXA) or the quantitative bone ultrasound (QUS) in independent elderly men. Serum PTH and 25-OH-Vitamin D3 were measured in 195 healthy elderly men (mean ...

OBJECTIVE To determine whether serum vitamin D levels are correlated with serum levels of alkaline phosphatase or not. STUDY DESIGN Cross-sectional, observational study. PLACE AND DURATION OF STUDY Multi-centre study, conducted at Liaquat National Hospital and Medical College, National Medical Centre and Medicare Hospital, Karachi, from January to October 2009. METHODOLOGY Patients attend...

background: recurrent miscarriage (rm) affects 2-5% of pregnant women. paternal lymphocyte immunotherapy is a common treatment for rm patients but the outcome has not been consistent. therefore, combined therapy with other immunosuppressive drugs such as 1 a, 25-dihydroxy-vitamin-d3 (vitamin d3) may improve the outcome. objectives: to investigate the effect of vitamin d3 on the balance of two e...