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Interaction of Physiological Mechanisms in Control of Muscle Glucose
Uptake
APS Endocrinology & Metabolism Section
David H. Wasserman and Maureen Charron
D.H. Wasserman, E. Barrett, M. Charron and P. Fueger
Muscle glucose uptake requires three steps. These
are glucose delivery to muscle, membrane transport into muscle, and
intracellular phosphorylation within muscle. Muscle glucose delivery is
determined by muscle blood flow and capillary recruitment. Membrane
transport is destermined by plasma membrane glucose transporter number and
intrinsic activity. The capacity to phosphorylate glucose is determined by
hexokinase (HK) II activity, cellular hexokinase II compartmentalization,
and the concentration of the hexokinase II inhibitor glucose 6-phosphate.
Muscle glucose uptake is regulated by and insulin resistance is due to an
alteration in one or more of these steps. Each one of these steps has been
studied in isolation and there is a considerable amount known about how they
are regulated independently. The importance of these processes, however
rest with the effectiveness with which these diverse mechanisms are
integrated in vivo. This symposium will focus on recent research
highlighting the functional significance of the individual steps that
comprise muscle glucose uptake during the fasted state, with exercise, and
during insulin stimulation.
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