�ber den Stoffwechsel des menschlichen Herzens

Keul, J.; Doll, E; Steim, H; Fleer, U; Reindell, H

doi:10.1007/bf00363207

Cited by 61 publications

(7 citation statements)

References 17 publications

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“…Furthermore, the deficit could reflect substrate use from myocardial glycogen or triglyceride stores. We do not think, however, that this is very likely because the lambs are assumed to be in a steady state (10). The role of endogenous myocardial stores of substrates has not been elucidated.…”

Section: Discussionmentioning

confidence: 97%

“…To assess the relative importance of each substrate for myocardial oxidative metabolism, we calculated the OER (10,17). It was calculated by assuming that during a steady state all of the substrate taken up by the myocardium is combusted, using the formula OER = (ACSsubstrate X N)/(ACSoXy,,), in which ACS is the aortocoronary sinus concentration difference and N represents the number of mol of oxygen required to completely combust 1 mol of substrate (25).…”

Section: Methodsmentioning

confidence: 99%

“…It was calculated by assuming that during a steady state all of the substrate taken up by the myocardium is combusted, using the formula OER = (ACSsubstrate X N)/(ACSoXy,,), in which ACS is the aortocoronary sinus concentration difference and N represents the number of mol of oxygen required to completely combust 1 mol of substrate (25). N~uc,s, = 6, N,y,,,te = 2.5, Nlactate = 3, N~-~~-butyrate = 4.5, Nacetoacetate = 4, NFFA = 25, and Ntrlglycerldes = 75 (10,17). N is obtained from the stoichiometric relationship between oxygen and the respective substrate when expressed in equivalent molar concentrations.…”

Section: Methodsmentioning

confidence: 99%

“…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%

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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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Section: Discussionmentioning

confidence: 97%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

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

et al. 1992

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“…Keul and colleagues [8,9] found that in the human heart at rest the contribution of fatty acids to oxidative metabolism was 34% and that the remaining part of energy required was obtained from carbohydrates. Oxidation of glucose and lactate accounted for 31% and 29% of total oxygen consumption, respectively.…”

Section: Introductionmentioning

confidence: 99%

Interrelationship between lactate and cardiac fatty acid metabolism

Vusse¹,

Groot

1992

Mol Cell Biochem

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This overview is presented, in the main, to summarize the following aspects of lactate and cardiac fatty acid metabolism: 1. The utilization of exogenous carbohydrates and fatty acids by the heart. 2. The competition between lactate and fatty acids in cardiac energy metabolism. 3. The effect of lactate on endogenous triacylglycerol homeostasis. 4. Lactate-induced impairment of functional recovery of the post-ischemic heart. 5. The effect of lactate on lipid metabolism in the ischemic and post-ischemic heart. 6. The consequences of hyperlactaemia for cardiac imaging.

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Gas Exchange in Exercise

Cerretelli

Prampero

1987

Comprehensive Physiology

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�ber den Stoffwechsel des menschlichen Herzens

Cited by 61 publications

References 17 publications

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

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

Interrelationship between lactate and cardiac fatty acid metabolism

Gas Exchange in Exercise

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