Microanalytical measurements of insulin-stimulated glucose transport in single cells

Ultrasensitive microanalytical methods provide a means to measure insulin-stimulated glucose transport in single cells, and have allowed investigation of the functional relationships between GLUT4 and hexokinase. Results obtained using microanalysis demonstrate that depending on the insulin concentration either glucose transport or glucose phosphorylation may limit glucose metabolism in cardiac myocytes. Evidence for coordinate regulation of GLUT4 and hexokinase expression in skeletal muscle fibers has also been obtained. In combination with microinjection, microanalysis is proving useful in investigating the signal transduction pathways involved in the stimulation of glucose transport and glycogen synthase by insulin. (C) 1996 Academic Press Ltd