Use of transport mutants to examine the identity and expression of GLUT isoforms in rat cardiac myoblasts

Li, Zhan; Zaniewska, Ewa; Lo, Theodore C. Y.

doi:10.1080/15216549700201111

Cited by 3 publications

(2 citation statements)

References 17 publications

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“…This contrasts with an earlier western blot study showing GLUT3 in testis and brain but not in the human heart (5). In rat cardiomyoblasts GLUT1, 3 and 4 were noted to be present but GLUT3 contributed more to high affinity hexose transport than GLUT1 (6). Taken together, these data suggest a more predominant role for GLUT3 during cardiac development.…”

Section: Glucose Transporter Expression In the Heartcontrasting

confidence: 99%

Glucose transport in the heart

2004

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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 cells.

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Section: Glucose Transporter Expression In the Heartcontrasting

confidence: 99%

Glucose transport in the heart

2004

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“…GLUT3 has been found in both adult and fetal heart. Compared with GLUT1 and GLUT4, GLUT3 has a much higher affinity for hexose (72, 131). Although the sequence of GLUT8 shares 29% identical to GLUT1, whether GLUT8 regulates glucose transport in the heart is still unknown.…”

Section: Glucose Transporter In the Heartmentioning

confidence: 99%

Glucose Transporters in Cardiac Metabolism and Hypertrophy

Shao

Tian

2015

Comprehensive Physiology

200

173

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The heart is adapted to utilize all classes of substrates to meet the high-energy demand, and it tightly regulates its substrate utilization in response to environmental changes. Although fatty acids are known as the predominant fuel for the adult heart at resting stage, the heart switches its substrate preference toward glucose during stress conditions such as ischemia and pathological hypertrophy. Notably, increasing evidence suggests that the loss of metabolic flexibility associated with increased reliance on glucose utilization contribute to the development of cardiac dysfunction. The changes in glucose metabolism in hypertrophied hearts include altered glucose transport and increased glycolysis. Despite the role of glucose as an energy source, changes in other nonenergy producing pathways related to glucose metabolism, such as hexosamine biosynthetic pathway and pentose phosphate pathway, are also observed in the diseased hearts. This article summarizes the current knowledge regarding the regulation of glucose transporter expression and translocation in the heart during physiological and pathological conditions. It also discusses the signaling mechanisms governing glucose uptake in cardiomyocytes, as well as the changes of cardiac glucose metabolism under disease conditions.

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