Glucose uptake of hepatocytes and pancreatic beta cells (in mice, but GLUT1 in human beta cells; see Reference 1). The high Km of GLUT2 allows for glucose sensing; rate of glucose entry is proportional to blood glucose levels. GLUT4 transporters are insulin sensitive, and are found in muscle and adipose tissue. As muscle is a principal storage site for glucose and adipose tissue for triglyceride (into which glucose can be converted for storage), GLUT4 is important in post-prandial uptake of excess glucose from the bloodstream. Moreover, several recent papers show that GLUT 4 is present in the brain also. The drug metformin
Blood glucose monitoring to fluorescent detection, via measurement of viscosity. Investigation of affinity-based sensors has shown that encapsulation by body tissue does not cause a drift of the sensor signal, but only a time lag of the signal compared to the direct measurement in blood. Some new technologies to monitor blood glucose levels will not require access to blood to read the glucose level. Non-invasive technologies include near IR detection, ultrasound<ref name="Diabetes U/S SMBG"></ref> and dielectric spectroscopy. These may free the person with diabetes from finger sticks to supply the drop of blood for blood glucose analysis. Most of the non-invasive methods under