A SODIUM-DEPENDENT AND ENERGY-DEPENDENT GLUCOSE-TRANSPORTER WITH SIMILARITIES TO SGLT1-2 IS EXPRESSED IN BOVINE CORTICAL VESSELS

In order to investigate glucose transport at the blood-brain barrier (BBB), glucose transport properties were studied pharmacologically with a novel model system of inverted bovine brain cortical arteries. These vessels displayed glucose transport characteristics of facilitative glucose transporters (GLUT1-5) and of sodium- and energy-dependent glucose transporters (SGLT1-2). So far, glucose transport in the central nervous system (CNS) has only been shown to be achieved by facilitative transporters, in particular by GLUT1 at the blood-brain barrier and in glial cells and by GLUT3 in a subset of neurons. We report here that a SGLT-like transporter might partake in glucose transport at the bovine BBB, as indicated by immunocytochemical analysis and by Western immunoblot analysis of cultured bovine brain endothelial cells. A RNA protection assay revealed the presence of a SGLT-like gene fragment in rabbit cortex.