Glucose transporter 3(orGLUT3), also known assolute carrier family 2, facilitated glucose transporter member 3(SLC2A3) is aproteinthat in humans is encoded by theSLC2A3gene. GLUT3facilitatesthe transport ofglucoseacross theplasma membranesof mammalian cells. GLUT3 is most known for its specific expression inneuronsand has originally been designated as the neuronal GLUT. GLUT3 has been studied in other cell types with specific glucose requirements, includingsperm, preimplantationembryos, circulatingwhite blood cellsandcarcinomacell lines. GLUT3 has both a higher affinity for glucose and at least a fivefold greater transport capacity than GLUT1, GLUT2 and GLUT4, which is particularly significant for its role in neuronal glucose transport, where ambient glucose levels are fivefold lower than in serum.