Ulfracytochemical Localization of the Erythrocyte/ HepG2-Type Glucose Transporter (GLUT1) in Cells of the Blood-Retinal Barrier in the Rat
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چکیده
The blood-retinal barrier is part of the blood-ocular barrier. Retinal pigment epithelial cells connected by tight junctions serve as an outer blood-retinal barrier, and the nonfenestrated endothelial cells of blood vessels sealed by tight junctions serve as an inner blood-retinal barrier. Using antibodies specific for the erythrocyte/HepG2-type glucose transporter (GLUTl), one isoform of facilitated-diffusion glucose transporters, it was found, by ultrastructural cytochemical examination, that GLUTl in the rat was localized at both the apical and basolateral plasma membranes of retinal pigment epithelial cells. The fenestrated endothelial cells of the underlying choriocapillaries were negative for GLUTl. In the inner retina, GLUTl was found at both the luminal and contraluminal plasma membranes of endothelial cells. These observations show that GLUTl is concentrated at the critical plasma membranes of the blood-retinal barrier and may serve as the machinery for glucose transport across the barrier. Invest Ophthalmol Vis Sci 33:377-383,1992
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