Vitamin D (vitD) low status is currently considered a main environmental factor in multiple sclerosis (MS) etiology and pathogenesis. VitD and its metabolites are highly hydrophobic and circulate mostly bound to the vitamin D binding protein (DBP) and with lower affinity to albumin, while less than 1% are in a free form. The aim of this study was to investigate whether the circulating levels of...

Previous studies report an association between vitamin D deficiency and hypertension, including the pregnancy-specific disorder preeclampsia. Circulating vitamin D is almost entirely bound to vitamin D binding protein, which increases 2-fold during pregnancy and previous studies have not examined vitamin D binding protein or free vitamin D levels. We performed a nested case-control study within...

Two mouse models in which the vitamin D-binding protein (DBP) or megalin, a DBP receptor, were knocked out have recently confirmed that DBP is essential for normal vitamin D homeostasis, and have revealed a major pathway for vitamin D activation (1, 2). DBP is also known as the group-specific component of serum (Gc-globulin). It is a highly polymorphic 58 kDa glycoprotein, which has been used a...

An automated immunonephelometric assay was developed to measure vitamin D-binding protein (DBP) in serum. The assay is described for the Behring Nephelometer System, which uses rabbit anti-DBP antiserum and purified human DBP. The detection limit is 0.05 g/L (0.86 mumol/L), and the working range is less than or equal to 1.60 g/L (27.59 mumol/L). Intra- and interassay CVs of 2.0% and 2.8-3.8% co...

A method of purification of a vitamin D-dependent calciumbinding protein from chick intestinal mucosa is described. The purification procedure involved the use of ammonium sulfate precipitation, gel filtration on Sephadex G-100, and preparative disc electrophoresis. The assay system for calcium-binding protein is based upon the competition between calcium-binding protein and an ion exchange res...

BACKGROUND Low levels of total 25-hydroxyvitamin D are common among black Americans. Vitamin D-binding protein has not been considered in the assessment of vitamin D deficiency. METHODS In the Healthy Aging in Neighborhoods of Diversity across the Life Span cohort of blacks and whites (2085 participants), we measured levels of total 25-hydroxyvitamin D, vitamin D-binding protein, and parathyr...

Vitamin D binding protein (DBP) is the major carrier protein of 25-hydroxyvitamin D (25(OH) D) in the circulation, where it may serve roles in maintaining stable levels during times of decreased 25(OH) availability and in regulating delivery of 25(OH) D to target tissues. Several genetic polymorphisms of DBP have been described that lead to phenotypic changes in the protein that may affect affi...