Formation and Breakdown of Uridine in Ischemic Hearts of Rats and Humans

Smoleński, Ryszard T.; Jong, Jan Willem de; Janssen, Mathieu F.; Lachno, D. Richard; Zydowo, M; Tavenier, Monique; Huizer, Tom; Yacoub, Magdi H.

doi:10.1006/jmcc.1993.1008

Cited by 32 publications

(10 citation statements)

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“…Ethanol has been shown to increase the plasma concentration of uridine presumably via an abrupt consumption of ATP, as do fructose, xylitol, muscular exercise, and ischemia. 1,[8][9][10][11][12] Because uridine diphosphate (UDP) is phosphorylated into uridine triphosphate (UTP) using ATP, a decrease in the concentration of ATP leads to an increase in the concentrations of UDP and UMP, resulting in an accelerated conversion of UMP to uridine. As a result, uridine is leaked into the blood, and its plasma level increases.…”

Section: Discussionmentioning

confidence: 99%

Effect of beer on the plasma concentrations of uridine and purine bases

et al. 2002

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Section: Discussionmentioning

confidence: 99%

Effect of beer on the plasma concentrations of uridine and purine bases

et al. 2002

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“…Crude homogenate was used for the assay ofmembrane-5'-nucleotidase. For all other enzyme assays, the homogenate was centrifuged at 3700 r.p.m, for 30 min at 4~ and assayed at 37~ as described previously [20][21][22]. The maximal enzyme activity was calculated from the rate of conversion of substrate into product.…”

Section: Enzyme Assaysmentioning

confidence: 99%

Hyperthyroidism increases adenosine transport and metabolism in the rat heart

1995

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Hyperthyroidism induces a number of metabolic and physiological changes in the heart including hypertrophy, increase in inotropic status, and alterations of myocardial energy metabolism. The effects of hyperthyroidism on adenosine metabolism which is intimately involved in the control of many aspects of myocardial energetics, have not been clarified. The aim of this study was thus to evaluate the potential role of adenosine in the altered physiology of the hyperthyroid heart. Transport of adenosine was studied in cardiomyocytes isolated from hyperthyroid and euthyroid rats. Activities of different enzymes of purine metabolism were studied in heart homogenates and concentrations of nucleotide and creatine metabolites were determined in hearts freeze-clamped in situ. Both transport of adenosine into cardiomyocytes and the rate of intracellular phosphorylation were higher in the hyperthyroid rat. At 10 microM concentration, adenosine transport rates were 275 and 197 pmol/min/mg protein in hyperthyroid and euthyroid cardiomyocytes respectively whilst rates of adenosine phosphorylation were 250 and 180 pmol/min/mg prot. An even more pronounced difference was observed if values were expressed per number of cells due to cardiomyocyte enlargement. Hyperthyroidism was associated with a 20% increase in adenosine kinase, 30% decrease in membrane 5'-nucleotidase and 15% decrease in adenosine deaminase activities measured in heart homogenates. In addition there was a substantial depletion in the total creatine pool from 63.7 to 41.6 mumol/g dry wt, a small decrease in the adenylate pool (from 27.2 to 24.3 mumol/g dry wt) and an elevation of the guanylate pool (from 1.22 to 1.36). These results show that adenosine transport and phosphorylation capacity is enhanced in hyperthyroidism.(ABSTRACT TRUNCATED AT 250 WORDS)

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“…We are inclined to attribute this finding to a significant reduction in arterial concentrations of Urd during reperfusion. Accumulation of Urd during ischaemia was also reported in the human heart, apparently because of low activities of uridine phosphorylase metabolizing Urd to uracil (Smolenski et al. 1993b).…”

Section: Discussionmentioning

confidence: 90%

Myocardial and coronary sinus purines as indicators of pig heart energy metabolism during reperfusion after extracorporeal circulation

Safranow

Rzeuski

Listewnik

et al. 2005

Acta Physiologica Scandinavica

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Coronary sinus concentrations of purines provide only a limited insight into the metabolism of the porcine heart. Repeated biopsies of the heart muscle and HPLC determinations of purine profiles represent a comprehensive and unique method for the study of purine metabolism during ischaemia and reperfusion. Future research on myocardial metabolism in disease and during cardiosurgical procedures should additionally be oriented to deficits in guanine and pyridine nucleotides.

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Formation and Breakdown of Uridine in Ischemic Hearts of Rats and Humans

Cited by 32 publications

References 0 publications

Effect of beer on the plasma concentrations of uridine and purine bases

Effect of beer on the plasma concentrations of uridine and purine bases

Hyperthyroidism increases adenosine transport and metabolism in the rat heart

Myocardial and coronary sinus purines as indicators of pig heart energy metabolism during reperfusion after extracorporeal circulation

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