BACKGROUND Interpretation of parathyroid hormone (iPTH) requires knowledge of vitamin D status that is influenced by season. OBJECTIVE Characterize the temporal relationship between 25-hydroxyvitamin D3 levels [25(OH)D3] and intact iPTH for several seasons, by gender and latitude in the U.S. and relate 25-hydrovitamin D2 [25(OH)D2] levels with PTH levels and total 25(OH)D levels. METHOD We ...

BACKGROUND The aims of this study were to determine if pregnant women consumed the recommended vitamin D through diet alone or through diet and supplements, and if they achieved the current reference range vitamin D status when their reported dietary intake met the current recommendations. METHODS Data and banked blood samples collected in second trimester from a subset of 537 women in the AP...

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...

The nuclear hormone 1α,25-dihydroxyvitamin D(3) (1α,25(OH)(2)D(3) or 1,25D) regulates its target genes via activation of the transcription factor vitamin D receptor (VDR) far more specifically than the chromatin modifier trichostatin A (TsA) via its inhibitory action on histone deacetylases. We selected the thrombomodulin gene locus with its complex pattern of five VDR binding sites and multipl...

BACKGROUND/AIMS Myocarditis is an important inflammatory disease of the heart which causes life-threatening conditions. 1, 25(OH)2 D3 has effects on multiple systems and diseases. The present study was aimed to investigate the effect of 1, 25(OH)2 D3 on experimental autoimmune myocarditis (EAM), and explored the underlying mechanisms involved. METHODS EAM was induced by immunizing BALB/c mice...

Given the distorted 1α-hydroxylase system in CKD patients, administration of precursors of vitamin D such as cholecalciferol (D3) or ergocalciferol (D2), also known as nutritional vitamin D agents, is often ineffective. Hence, active vitamin D analogues including synthetic calcitriol and alfacalcidol (which increase the circulating levels of 1α,25(OH) 2 D) or vitamin D mimetics including parica...

BACKGROUND Recommendations for vitamin D supplementation for preterm infants span a wide range of doses. Response to vitamin D supplementation and impact on outcomes in preterm infants is not well understood. OBJECTIVE Evaluate serum 25(OH)D3 concentration changes after 4 weeks in response to two different doses of vitamin D3 supplementation in a population of premature infants and quantify t...

BACKGROUND Associations between vitamin D and pregnancy outcomes have been inconsistent. OBJECTIVES We described the distribution of 25-hydroxyvitamin D3 [25(OH)D3], 3-epi-25(OH)D3, and 25(OH)D2 in early pregnancy and investigated associations with pre-eclampsia and small-for-gestational-age (SGA) birth, which are indicative of uteroplacental dysfunction. DESIGN The SCOPE (Screening for Pre...

The vitamin D receptor (VDR) serves as a for active hydroxyderivatives. formation of hydroxyderivatives requires the presence specific cytochrome P450 (CYP) enzymes metabolism. These can be further hydroxylated by CYP27B1 at C1α-position which increases their affinity VDR. However, role in antiproliferative and antifibrotic activities CYP11A1-derived D3-metabolites is unknown. We tested action ...

A primary chick kidney cell culture is described, capable of forming 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], 24,25-dihydroxyvitamin D3 [24,25(OH)2D3], and 1,24,25-trihydroxyvitamin D3 [1,24,25(OH)3D3] over several days. The apparent Km values were 0.125 microM for the 1-hydroxylase and 2.1 microM for the 24-hydroxylase. Exogenous 1,25(OH)2D3 decreased 1-hydroxylase and increased 24-hydroxylase ...