Myocardial lipid and carbohydrate metabolism in fasting men during prolonged exercise.

Kaijser, L.; Lassers, B. W.; Wahlqvist, Mark L.; Carlson, L. A.

doi:10.1152/jappl.1972.32.6.847

Cited by 48 publications

(28 citation statements)

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“…Since arterial oxygen content was unchanged, salbutamol must have allowed an increase in coronary blood flow, sufficient to supply the increased oxygen requirements which would have accompanied the tachycardia, without an increased myocardial extraction of oxygen. This is of particular interest since the physiological tachycardia of exercise does lead to an increased myocardial extraction of oxygen, as well as an increased coronary flow (Kaijser, Lassers, Wahlqvist & Carlson, 1972). These findings are consistent with those of Nayler (1971) in respect of a direct coronary vasodilator effect of salbutamol and of Nayler & McInnes (1972) in regard to the maintenance of myocardial efficiency with salbutamol.…”

Section: Discussionsupporting

confidence: 81%

EFFECTS OF β₂‐ADRENOCEPTOR STIMULATION ON CARDIAC METABOLISM IN THE CONSCIOUS DOG

Shanahan

Wahlqvist

Wilmshurst

1979

British J Pharmacology

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The effects of the β2‐adrenoceptor stimulant, salbutamol, on cardiac metabolism have been studied in conscious mongrel dogs. The potential effects of anaesthesia on the study of cardiac metabolism have been avoided by prior implantation of arterial (A) and coronary sinus (CS) catheters for blood sampling and a central venous catheter for infusion. Extraction of substrates for myocardial energy metabolism (CA—CS) was assessed 3 to 24 days post‐operatively. A 100 μg bolus of salbutamol was given followed by an infusion of 3 μg/min for 1 h. Although heart rate increased significantly from 106 to 165 beats/min, fractional extraction of oxygen tended to fall from 84% to 77%. Thus an increase in coronary blood flow rather than in oxygen extraction must have maintained an oxygen supply commensurate with the salbutamol‐induced tachycardia. Neither CA—CS glucose nor fractional glucose extraction altered significantly during salbutamol infusion despite increases in arterial concentration (CA) of glucose and arterial insulin immunoreactivity and a decrease in CA of free fatty acids (FFA). This suggests that an insulin‐antagonistic action accompanies the infusion of salbutamol. The fractional extraction of lactate increased during salbutamol infusion. In part, this may have been a reflection of a decreased myocardial extraction of FFA with salbutamol in this model.

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Section: Discussionsupporting

confidence: 81%

EFFECTS OF β₂‐ADRENOCEPTOR STIMULATION ON CARDIAC METABOLISM IN THE CONSCIOUS DOG

Shanahan

Wahlqvist

Wilmshurst

1979

British J Pharmacology

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“…The respiratory quotient also increased, indicating a shift in myocardial metabolism to aerobic glycolysis. Kaijser and his associates (31) have also examined carbohydrate extraction by the human heart during exercise or glucose infusion. During exercise, plasma FFA rose markedly while insulin and glucose declined, and heart uptake of FFA but not glucose increased (31).…”

Section: Discussionmentioning

confidence: 99%

“…Kaijser and his associates (31) have also examined carbohydrate extraction by the human heart during exercise or glucose infusion. During exercise, plasma FFA rose markedly while insulin and glucose declined, and heart uptake of FFA but not glucose increased (31). In contrast, during glucose infusion, plasma glucose and insulin and myocardial glucose uptake rose while plasma levels and myocardial removal of FFA declined.…”

Section: Discussionmentioning

confidence: 99%

Regulation by insulin of myocardial glucose and fatty acid metabolism in the conscious dog.

Barrett¹,

Schwartz²,

Francis³

et al. 1984

J. Clin. Invest.

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As bstract. In vivo small doses of insulin inhibit lipolysis, lower plasma FFA, and stimulate glucose disposal. Lowering of plasma FFA, either in the absence of a change in insulin or during combined hyperglycemia and hyperinsulinemia, promotes glucose uptake by heart muscle in vivo. In the isolated perfused heart, large doses of insulin directly stimulate heart glucose uptake. To assess the effect of physiological elevations of plasma insulin upon myocardial glucose and FFA uptake in vivo independent of changes in plasma substrate concentration, we measured arterial and coronary sinus concentrations ofglucose, lactate, and FFA, and coronary blood flow in conscious dogs during a 30 min basal and a 2 h experimental period employing three protocols: (a) euglycemic hyperinsulinemia (insulin clamp, n = 5), (b) euglycemic hyperinsulinemia with FFA replacement (n = 5), (c) hyperglycemic euinsulinemia (hyperglycemic clamp with somatostatin, n = 5).In group 1, hyperinsulinemia (insulin = 73±13 MU/ ml) stimulated heart glucose uptake (7.3±4.4 vs. 28.2±2.8 Mmol/min, P < 0.002), lowered plasma FFA levels by 80% (P < 0.05), and decreased heart FFA uptake (28.4±4 vs. 1.5±0.9, P < 0.01). When the fall in plasma FFA was prevented by FFA infusion (group 2), hyperinsulinemia (86 ± 10 ,U/ml) provoked a lesser (P < 0.05) stimulation of glucose uptake (A = 8.2±4.2 ,mol/min) (plasma glucose = 186±8 mg/100 ml) during somatostatin infusion resulted in only a small rise in plasma insulin (A = 12±7 ,U/ml), and although plasma FFA tended to decline, heart glucose uptake did not rise significantly (A = 5.5±3.2 Amol/min, P = NS). There was no significant change in coronary blood flow during any of the three study protocols.We conclude that, in the dog, insulin at physiologic concentrations: (a) stimulates heart glucose uptake, both directly and by suppressing the plasma FFA concentration, and (b) does not alter coronary blood flow. Hyperglycemia per se has little effect on heart glucose uptake.

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“…This effect is accompanied by an increased myocardial oxygen consumption (3), which reflects increased oxidation of substrates to meet the increased ATP demand (4). Often, an increased work load leads not only to increased substrate uptake, but also to a change in the pattern of myocardial substrate utilization (5), as has been shown in hearts with increased afterload (6), contractility (7), and thyroxineinduced volume load (8, 9) and during exercise (5,(10)(11)(12). Furthermore, catecholamines are often increased in the presence of a substantial left to right shunt (13), and they are also known to affect myocardial metabolism (14,15).…”

mentioning

confidence: 99%

“…In addition to the effects on myocardial oxygen consumption mentioned above, adverse effects of enhanced fatty acid uptake on myocardial performance have also been reported in isolated hearts (1 9-22). If, instead of an increase in fatty acid uptake, a shift toward increased glucose or lactate uptake would occur, as occurs during the increased myocardial work accompanying exercise (1 0- 12,17), this would probably not be unfavorable. This is supported by the finding that enhanced glucose utilization decreases myocardial oxygen consumption (23).…”

mentioning

confidence: 99%

Myocardial Carbohydrate, Ketone, and Fatty Acid Uptake in Conscious Lambs with Aortopulmonary Shunts1

et al. 1992

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ABSTRACT. A left to right shunt increases myocardial work and is often accompanied by increased catecholamine levels. Because both increased myocardial work and increased catecholamine levels may induce increased fatty acid utilization, which could increase resting myocardial oxygen consumption and therefore unfavorably affect coronary reserve, we studied myocardial uptake of glucose, pyruvate, lactate, &OH-butyrate, acetoacetate, FFA, and triglycerides in 12 7-wk-old lambs with aortopulmonary left to right shunts (58 f 2% of left ventricular output, mean f SEM) and in 10 control lambs 2 wk after surgery. Despite the shunt, systemic blood flow in the shunt lambs was maintained at the same level as in the control lambs. This was accomplished by an increased heart rate and stroke volume. Furthermore, the shunt was accompanied by an increased myocardial oxygen consumption in the shunt lambs (834 f 70 versus 528 f 43 pmol 02-mine' -100 g-I; p c 0.05). There were no significant differences in arterial substrate concentrations between the two groups. The same was true for arteriovenous differences across the myocardium, with the exception of lactate, which was substantially higher in shunt than in control lambs (72 f 25 versus 18 f 23 pmol/L; p < 0.05). As a consequence, myocardial lactate uptake in the shunt lambs was increased 15-fold (18 2 6 versus 1 f 2 pmol. min-I. 100 g-I; p c 0.02), whereas uptake of the other substrates merely paralleled the increased myocardial blood flow. Our data demonstrate that myocardial substrate uptake is not substantially different between shunt and control lambs, with the exception of lactate, of which the extraction is 10-fold higher than in control lambs. We speculate that the increased myocardial lactate utilization may reflect an increase of lactate and pyruvate dehydrogenase activities. A left to right shunt through a ventricular septa1 defect or ductus arteriosus imposes an increased work load on the heart because of its effect on left ventricular wall stress, external work, contractility, and heart rate (1-3). This effect is accompanied by an increased myocardial oxygen consumption (3), which reflects increased oxidation of substrates to meet the increased ATP demand (4). Often, an increased work load leads not only to increased substrate uptake, but also to a change in the pattern of myocardial substrate utilization (5), as has been shown in hearts with increased afterload (6), contractility (7), and thyroxineinduced volume load (8, 9) and during exercise (5,(10)(11)(12). Furthermore, catecholamines are often increased in the presence of a substantial left to right shunt (13), and they are also known to affect myocardial metabolism (14,15). Through their effect on myocardial performance, catecholamines stimulate glucose and fatty acid utilization by the myocardium, and, through activation of lipoprotein lipase, they enhance fatty acid utilization (5, [14][15][16].These considerations suggest that a left to right shunt could lead to a change in myocardial substrate metabolism....

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Myocardial lipid and carbohydrate metabolism in fasting men during prolonged exercise.

Cited by 48 publications

References 0 publications

EFFECTS OF β₂‐ADRENOCEPTOR STIMULATION ON CARDIAC METABOLISM IN THE CONSCIOUS DOG

EFFECTS OF β₂‐ADRENOCEPTOR STIMULATION ON CARDIAC METABOLISM IN THE CONSCIOUS DOG

Regulation by insulin of myocardial glucose and fatty acid metabolism in the conscious dog.

Myocardial Carbohydrate, Ketone, and Fatty Acid Uptake in Conscious Lambs with Aortopulmonary Shunts1

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Myocardial lipid and carbohydrate metabolism in fasting men during prolonged exercise.

Cited by 48 publications

References 0 publications

EFFECTS OF β2‐ADRENOCEPTOR STIMULATION ON CARDIAC METABOLISM IN THE CONSCIOUS DOG

EFFECTS OF β2‐ADRENOCEPTOR STIMULATION ON CARDIAC METABOLISM IN THE CONSCIOUS DOG

Regulation by insulin of myocardial glucose and fatty acid metabolism in the conscious dog.

Myocardial Carbohydrate, Ketone, and Fatty Acid Uptake in Conscious Lambs with Aortopulmonary Shunts1

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EFFECTS OF β₂‐ADRENOCEPTOR STIMULATION ON CARDIAC METABOLISM IN THE CONSCIOUS DOG

EFFECTS OF β₂‐ADRENOCEPTOR STIMULATION ON CARDIAC METABOLISM IN THE CONSCIOUS DOG