Localization of cellular retinol-binding protein and retinol-binding protein in cells comprising the blood-brain barrier of rat and human.
Brain is not generally recognized as an organ that requires vitamin A, perhaps because no obvious histologic lesions have been observed in severely vitamin A-deficient animals. However, brain tissue does contain cellular vitamin A-binding proteins and a nuclear receptor protein for retinoic acid. In the present study, immunohistochemical techniques were used to determine the cell-specific location of cellular retinol-binding protein in human and rat brain tissue. Cellular retinol-binding protein was localized specifically within the endothelial cells of the brain microvasculature and within the cuboidal epithelial cells of the choroid plexus, two primary sites of the mammalian blood-brain barrier. In addition, autoradiographic procedures demonstrated binding sites for serum retinol-binding protein in the choroidal epithelium. These observations suggest that a significant movement of retinol across the blood-brain barrier may occur.
Department of Biochemistry, Vanderbilt University, Nashville, TN 37232.
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MacDonald
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D
Bok
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Ong
D000818:Animals; D001345:Autoradiography; D001812:Blood-Brain Barrier; D002831:Choroid Plexus / Q000378:metabolism; D004730:Endothelium, Vascular / Q000378:metabolism; D004848:Epithelium / Q000378:metabolism; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D051381:Rats; D012177:Retinol-Binding Proteins / Q000378:metabolism*; D054840:Retinol-Binding Proteins, Cellular; D014801:Vitamin A / Q000378:metabolism
D012177:Retinol-Binding Proteins; D054840:Retinol-Binding Proteins, Cellular; D014801:Vitamin A