In a classical sense, vitamin D3, the form produced in animals, is not a true “vitamin” because it is produced in the skin from 7-dehydrocholesterol by UV radiation in the range 290 to 300 nm; 7-dehydrocholesterol is produced from cholesterol metabolism. Only when exposure to sunlight is inadequate does vitamin D3 become a vitamin in the historical sense. Further, vitamin D3 is now termed a pro...

It has been shown that mammalian cytochrome P450scc can metabolize vitamin D3 to 20-hydroxyvitamin D3 (20(OH)D3) and 20,22(OH)2D3. To define the biological significance of this pathway, we tested the effects of 20(OH)D3 on the differentiation program of keratinocytes and on the expression of enzymes engaged in vitamin D3 metabolism. Immortalized HaCaT and adult human epidermal keratinocytes wer...

Background: Several lines of evidence suggest that oxidized LDL (Ox-LDL) scavenger receptors play a crucial role in the genesis and progression of diabetic atherosclerosis. This study aimed to elucidate the effect of vitamin D3 on gene expression of lectin-like oxidized LDL receptor-1 (LOX-1), scavenger receptor-A (SR-A), Cluster of Differentiation 36 (CD36), and Cluster of Differentiation 68 (...

Background: One strategy for improving population vitamin D status is consumption of fortified foods. However, the effects of dairy products fortified with different vitamin D isoforms on postprandial vitamin D status and metabolic outcomes have not been addressed.Objective: We investigated whether consumption of dairy drinks fortified with either 25-hydroxycholecalciferol [25(OH)D3] or choleca...

After injection of 3H 1,25 (OH)2 vitamin D3 to adult rats and mice, under normal or vitamin D deficient diet, the hormone was found to be accumulated in nuclei of neurons in certain brain regions. Nuclear concentration was prevented or diminished, when excess unlabeled 1,25 (OH)2 vitamin D3 was injected before 3H 1,25 (OH)2 vitamin D3, while excess 25 (OH) vitamin D3 did not prevent nuclear lab...

BACKGROUND In our previous study, higher serum 25-hydroxyvitamin D [25(OH)D] concentrations and the vitamin D receptor (VDR) FokI CC genotype were associated with milder Parkinson disease (PD). OBJECTIVE We evaluated whether vitamin D3 supplementation inhibits the progression of PD on the basis of patient VDR subgroups. DESIGN Patients with PD (n = 114) were randomly assigned to receive vit...

Objective: The influence of vitamin D receptor (VDR) genetic variation on serum 25-hydroxyvitamin D levels [25(OH)D] after vitamin D3 supplementation remains unclear. We aimed to investigate changes of 25(OH)D in a randomized, double-blind, placebo-controlled clinical trial, according to VDR genotype, after provision of vitamin D3 to breast cancer cases for a 2-month period. Methods: Participan...

ΔNp63α, a proto-oncogene, is up-regulated in non-melanoma skin cancers and directly regulates the expression of both Vitamin D receptor (VDR) and phosphatase and tensin homologue deleted on chromosome ten (PTEN). Since ΔNp63α has been shown to inhibit cell invasion via regulation of VDR, we wanted to determine whether dietary Vitamin D3 protected against UVB induced tumor formation in SKH-1 mic...

In order to better understand vitamin D3 in cattle metabolism, we quantified 1alpha-HYD and 24-HYD gene expression. In the kidneys of 35 male Nellore cattle, these were divided into a control group and two treatment groups (2 x 10(6) international units of vitamin D3 administered for 2 or 8 consecutive days pre-slaughter). Vitamin D3 supplementation resulted in a significant increase in 1alpha-...

Background and Objectives: : Vitamin D3 measurement in food and fortified food matrixes is usually interrupted by several variables. This study aimed to elaborate a specific vitamin D3 quantification method for fortified Taftoon bread considering different influential variables in each step of measurement. Materials and Methods: Dough was fortified with (4μg/100g) and the sta...