Journal article
Creatine transporter activity and content in the rat heart supplemented by and depleted of creatine
- Boehm, Ernest Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN; Department of Biochemistry, University of Oxford, Oxford OX1 3BN, United Kingdom; and Eidgenoessisch-technische Hochschule (ETH)-Zürich, Institute of Cell Biology, ETH-Hönggerberg, CH-8093 Zürich, Switzerland
- Chan, Sharon Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN; Department of Biochemistry, University of Oxford, Oxford OX1 3BN, United Kingdom; and Eidgenoessisch-technische Hochschule (ETH)-Zürich, Institute of Cell Biology, ETH-Hönggerberg, CH-8093 Zürich, Switzerland
- Monfared, Mina Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN; Department of Biochemistry, University of Oxford, Oxford OX1 3BN, United Kingdom; and Eidgenoessisch-technische Hochschule (ETH)-Zürich, Institute of Cell Biology, ETH-Hönggerberg, CH-8093 Zürich, Switzerland
- Wallimann, Theo Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN; Department of Biochemistry, University of Oxford, Oxford OX1 3BN, United Kingdom; and Eidgenoessisch-technische Hochschule (ETH)-Zürich, Institute of Cell Biology, ETH-Hönggerberg, CH-8093 Zürich, Switzerland
- Clarke, Kieran Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN; Department of Biochemistry, University of Oxford, Oxford OX1 3BN, United Kingdom; and Eidgenoessisch-technische Hochschule (ETH)-Zürich, Institute of Cell Biology, ETH-Hönggerberg, CH-8093 Zürich, Switzerland
- Neubauer, Stefan Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN; Department of Biochemistry, University of Oxford, Oxford OX1 3BN, United Kingdom; and Eidgenoessisch-technische Hochschule (ETH)-Zürich, Institute of Cell Biology, ETH-Hönggerberg, CH-8093 Zürich, Switzerland
Published in:
- American Journal of Physiology-Endocrinology and Metabolism. - American Physiological Society. - 2003, vol. 284, no. 2, p. E399-E406
English
The intracellular creatine concentration is an important bioenergetic parameter in cardiac muscle. Although creatine uptake is known to be via a NaCl-dependent creatine transporter (CrT), its localization and regulation are poorly understood. We investigated CrT kinetics in isolated perfused hearts and, by using cardiomyocytes, measured CrT content at the plasma membrane or in total lysates. Rats were fed control diet or diet supplemented with creatine or the creatine analog β-guanidinopropionic acid (β-GPA). Creatine transport in control hearts followed saturation kinetics with a K m of 70 ± 13 mM and a V max of 3.7 ± 0.07 nmol · min−1 · g wet wt−1 . Creatine supplementation significantly decreased the V max of the CrT (2.7 ± 0.17 nmol · min−1 · g wet wt−1 ). This was matched by an ∼35% decrease in the plasma membrane CrT; the total CrT pool was unchanged. Rats fed β-GPA exhibited a >80% decrease in tissue creatine and increase in β-GPAtotal . The V max of the CrT was increased (6.0 ± 0.25 nmol · min−1 · g wet wt−1 ) and the K m decreased (39.8 ± 3.0 mM). The plasma membrane CrT increased about fivefold, whereas the total CrT pool remained unchanged. We conclude that, in heart, creatine transport is determined by the content of a plasma membrane isoform of the CrT but not by the total cellular CrT pool.
- Language
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- English
- Open access status
- closed
- Identifiers
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- DOI 10.1152/ajpendo.00259.2002
- ISSN 0193-1849
- Persistent URL
- https://sonar.ch/global/documents/66991
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