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Real-time Analyses of Retinol Transport by the Membrane Receptor of Plasma Retinol Binding Protein
Published on: January 28, 2013
Vitamin D binding factors in bovine blood
Journal of Dairy Science
|October 1, 1977
Summary
Vitamin D circulates in blood bound to alpha-globulin, a protein with high affinity for its metabolites. Alpha-lipoprotein may assist vitamin D transport from the gut to the liver.
Area of Science:
- Biochemistry
- Endocrinology
- Nutritional Science
Background:
- Vitamin D is crucial for calcium homeostasis and bone health.
- Understanding vitamin D transport in blood is essential for its metabolic regulation.
Purpose of the Study:
- To identify the plasma proteins responsible for vitamin D and its metabolite transport in bovine plasma.
- To elucidate the binding affinities and dynamics between vitamin D, its metabolites, and carrier proteins.
Main Methods:
- In vitro incubation of bovine plasma with 25-hydroxycholecalciferol and cholecalciferol.
- Analysis using gel-filtration, ion exchange chromatography, electrophoresis, ultracentrifugation, competitive binding studies, and plasma stripping.
Main Results:
- Vitamin D circulates bound to an alpha-globulin with a molecular weight of approximately 70,000.
- This alpha-globulin exhibits a high affinity for 25-hydroxycholecalciferol.
- Vitamin D3 initially associates with an alpha-lipoprotein before binding to the alpha-globulin.
Conclusions:
- Alpha-globulin is identified as the primary carrier protein for vitamin D in bovine blood.
- Alpha-lipoprotein may play a role in facilitating cholecalciferol transfer from the gut to the liver.
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