Myocardial extraction of glucose, lactate, and pyruvate in normal dogs was directly related to arterial levels, with glucose as the main fuel at normal levels and fat during starvation.
How do hyperglycemia and starvation affect myocardial carbohydrate metabolism in normal dogs?
This preclinical study demonstrates that myocardial glucose extraction is dependent on arterial levels and that the heart shifts to fat metabolism during starvation.
Myocardial metabolism of Nembutalized normal intact dogs was studied with the aid of the coronary sinus catheterization technic. Oxygen, glucose, lactate and pyruvate were extracted by the heart in direct relation to the arterial level of each substance, independently of the others. Pyruvate and lactate showed a high myocarcdial extraction coefficient, but the normal low arterial levels at rest prevented them from together accounting for more than 50 per cent of the total myocardial energy requirements. Glucose was not utilized below a mean threshold of 54 mg. per cent, but with normal arterial levels of 70 to 120 mg. per cent, glucose extraction was sufficient to provide the major potential source of fuel for myocardial oxidative energy. During starvation, the heart probably derived its energy from fat, as indicated by a myocardial respiratory quotient near 0.70, and a low myocardial carbohydrate extraction.
Goodale et al. (Sun,) conducted a other in Normal intact dogs. Hyperglycemia and starvation vs. Normal resting state was evaluated on Myocardial extraction of oxygen, glucose, lactate and pyruvate. Myocardial extraction of glucose, lactate, and pyruvate in normal dogs was directly related to arterial levels, with glucose as the main fuel at normal levels and fat during starvation.
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