Overview Sodium/glucose cotransporter (SGLT) function transport glucose actively across lumen against concentration gradient energy provided by transport of sodium down its concentration gradient location small intestine (SGLT1) 2:1 Na+:Glu proximal tubule of nephron (SGLT2) 1:1 Na+:Glu Glucose transporters (GLUT) function facilitated diffusion of glucose down concentration gradients with increasing glucose concentration, rate of transport assumes a hyperbolic curve due to carrier saturation divided into many subtypes that localize to different tissues GLUT-1 function basal glucose uptake high affinity transporters saturated at normal blood glucose levels ensures glucose entry to cells location wide distribution in tissues in the body (brain, erythrocytes, endothelial cells, cornea etc.) GLUT-2 function low affinity glucose uptake in the fasting state glucose does not enter cells mediates glucose surplus storage in liver when blood glucose levels rise facilitates insulin release in β-cells location hepatocytes pancreatic β-cells kidney small intestines GLUT-3 function high affinity glucose uptake glucose preferentially accessed by neurons in low-glucose states location brain neurons GLUT-4 function insulin-controlled uptake of glucose basal level of glucose intake without insulin presence of insulin ↑ translocation of transporters to the cell membrane ↑↑↑ glucose uptake also stimulated by exercise location adipocytes myocytes cardiomyocytes