Glucose transport in the heart.
Authors Abel ED.
Submitted By E. Dale Abel on 3/12/2004
Status Published
Journal Frontiers in bioscience
Year 2004
Date Published 6/1/2004
Volume : Pages 9 : 201 - 215
PubMed Reference 14766360
Abstract The heart is a unique organ in many ways. It consists of specialized muscle
cells (cardiomyocytes), which are adapted to contract constantly in a
coordinated fashion. This is vital to the survival of the organism given the
central role of the heart in the maintenance of the cardiovascular system that
delivers oxygen, metabolic substrates and hormones to the rest of the body. In
order for the heart to maintain its function it must receive a constant supply
of metabolic substrates, to generate ATP to maintain contractile function,
without fatigue. Thus the heart is capable of utilizing a variety of metabolic
substrates and is able to rapidly adapt its substrate utilization in the face of
changes in substrate supply. The major metabolic substrate for the heart is
fatty acids. However, up to 30% of myocardial ATP is generated by glucose and
lactate, with smaller contributions from ketones and amino acids. Although
glucose is not the major metabolic substrate in the heart at rest, there are
many circumstances in which it assumes greater importance such as during
ischemia, increased workload and pressure overload hypertrophy. Like all other
cells, glucose is transported into cardiac myocytes by members of the family of
facilitative glucose transporters (GLUTs). In this regard, cardiomyocytes bear
many similarities to skeletal muscle, but there are also important differences.
For example, the most abundant glucose transporter in the heart is the GLUT4
transporter, in which translocation to the plasma membrane represents an
important mechanism by which the net flux of glucose into the cell is regulated.
Because cardiomyocytes are constantly contracting it is likely that contraction
mediated GLUT4 translocation represents an important mechanism that governs the
entry of glucose into the heart. While this is also true in skeletal muscle,
because many muscles are often at rest, insulin mediated GLUT4 translocation
represents a quantitatively more important mechanism regulating skeletal muscle
glucose uptake than is the case in the heart. In contrast to skeletal muscle,
where most GLUT1 is in perineural sheaths (1), in the heart there is significant
expression of GLUT1 (2), which under certain circumstances is responsible for a
significant component of basal cardiac glucose uptake. This review will
summarize the current state of knowledge regarding the regulation of glucose
transporter expression, and the regulation of glucose transport into myocardial


Slc1a3solute carrier family 1, member 3
Slc2a1solute carrier family 2 (facilitated glucose transporter), member 1
Slc2a4solute carrier family 2 (facilitated glucose transporter), member 4