Sixteen crossbred (British x Continental; average un-shrunk body weight = 507.9 kg; SD = 45.6 kg) beef heifers fed a steam-flaked corn-based finishing diet with melengestrol acetate (0.4 mg/heifer daily) included to suppress estrus were used in a completely random design to evaluate the efficacy of buccal administration of 0, 10, 100, or 1000 mg of 25-hydroxyvitamin D3, (25-OH D3). Serum Ca, P,...

Pregnancy and lactation are associated with changes in vitamin D and calcium metabolism but the impact of these changes on vitamin D expenditure is unknown. We measured plasma 25(OH)D3 half-life with a stable-isotope tracer and investigated relationships with vitamin D metabolites in pregnant, lactating and 'non-pregnant, non-lactating' (NPNL) women. Vitamin D metabolites, vitamin D binding pro...

Key circulating molecules that link vitamin D (VD) to pediatric obesity and its co-morbidities remain unclear. Using a proteomic approach, our objective was to identify key molecules in obese children dichotomized according to 25OH-vitamin D (25OHD) levels. A total of 42 obese children (M/F = 18/24) were divided according to their 25OHD3 levels into 25OHD3 deficient (VDD; n = 18; 25OHD<15 ng/ml...

Low circulating levels of vitamin D and high mammographic density (MD) have been associated with higher risk of breast cancer. Although some evidence suggested an inverse association between circulating vitamin D and MD, no studies have investigated this association among Mexican women. We examined whether serum 25-hydroxyvitamin D3 [25(OH)D3] levels were associated with MD in a cross-sectional...

Metabolism of [3H]25-hydroxyvitamin D3(25-OH-D3) was studied in primary cultures of pulmonary alveolar macrophages (PAM) from seven patients with sarcoidosis and two patients with idiopathic pulmonary fibrosis. Production of a [3H]1,25-dihydroxyvitamin D3 (1,25-[OH]2-D3)-like metabolite of [3H]25-OH-D3 was detected in lipid extracts of cells from five patients with sarcoidosis. Synthesis of thi...

1. The term vitamin D is used for a range of closely related steroid compounds which possess the property of preventing or curing vitamin D deficiency. These include alfacalcidol (1α-hydroxyvitamin D3), calcifediol (25-hydroxyvitamin D3), calcitriol (1α,25 dihydroxy-vitamin D3), cholecalciferol (vitamin D3), dihydrotachysterol and ergocalciferol (vitamin D2 or calciferol). In veterinary medicin...

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...

CYP24A1 is a mitochondrial cytochrome P450 (CYP) that catabolizes 1α,25-dihydroxyvitamin D(3) (1α,25-(OH)(2)D(3)) to different products: calcitroic acid or 1α,25-(OH)(2)D(3)-26,23-lactone via multistep pathways commencing with C24 and C23 hydroxylation, respectively. Despite the ability of CYP24A1 to catabolize a wide range of 25-hydroxylated analogs including 25-hydroxyvitamin D(3), the enzyme...

Waterhouse et al. criticized the association between vitamin D intake and the prevention of pancreatic cancer (1), an association that has been thoroughly reviewed in recent years (2, 3). Yet, randomized controlled clinical trials (RCTs) very rarely produced encouraging and reliable results on the field (4–7). Negative evidence in animal models and experimental studies (8, 9) should suggest tha...