MICROANALYTICAL MEASUREMENTS OF INSULIN-STIMULATED GLUCOSE-TRANSPORT IN SINGLE CELLS

Ultrasensitive microanalytical methods provide a means to measure insu lin-stimulated glucose transport in single cells, and have allowed inv estigation of the functional relationships between GLUT4 and hexokinas e. Results obtained using microanalysis demonstrate that depending on the insulin concentration either glucose transport or glucose phosphor ylation 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 microinjecti on, microanalysis is proving useful in investigating the signal transd uction pathways involved in the stimulation of glucose transport and g lycogen synthase by insulin. (C) 1996 Academic Press Ltd