Adenine nucleotide synthesis de novo in mature rat cardiac myocytes

Dow, Jocelyn W.; Nigdikar, Shailja; Bowditch, Julia

doi:10.1016/0167-4889(85)90024-2

Cited by 12 publications

(4 citation statements)

References 13 publications

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“…Hence, we tested the ability of ribose to overcome the glucose deficiency in FSH-treated, hypoxanthine-arrested oocytes. Consistent with other studies in which exogenous ribose augmented levels of PRPP and purine nucleotide production [46][47][48], this pentose stimulated meiotic maturation, though it was effective at lower concentrations in the presence of FSH. These findings bolster the idea that end products of the oxidative arm of the PPP participate in meiotic induction.…”

Section: Discussionsupporting

confidence: 90%

“…Some cells can utilize exogenous ribose, converting it to ribose-5-phosphate and thereafter to PRPP and purine nucleotides, thus obviating a requirement for the oxidative arm of the PPP for purine synthesis [46][47][48][49]. To determine whether ribose could serve a similar function in the present system, cumulus cell-enclosed oocytes were cultured for 17-18 h in hypoxanthine-supplemented medium lacking glucose and containing 0.1 mM pyruvate, in the presence or absence of FSH.…”

Section: Resultsmentioning

confidence: 99%

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Meiotic Induction in Cumulus Cell-Enclosed Mouse Oocytes: Involvement of the Pentose Phosphate Pathway1

Downs¹,

Humpherson²,

Leese³

1998

Biology of Reproduction

128

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In this study we tested the hypothesis that the pentose phosphate pathway (PPP) participates in the meiotic induction of mouse oocytes. The electron acceptors methylene blue, phenazine ethosulfate (PES), and pyrroline-5-carboxylate (P5C) oxidize NADPH to NADP and activate the NADP-dependent enzymes of the PPP. Each of these compounds triggered a dose-dependent increase in meiotic maturation in hypoxanthine-arrested cumulus cell-enclosed oocytes during 17- to 18-h cultures. More than 96% of the oocytes underwent germinal vesicle breakdown (GVB) at the highest concentrations of P5C and PES tested (250 and 1 microM, respectively) as compared to only 45-52% of control oocytes. P5C was also stimulatory to denuded oocytes. Analysis of energy substrates in microdrop cultures revealed a 3.6-fold increase in glucose consumption by PES-treated oocyte-cumulus cell complexes that was associated with stimulation of GVB. On the other hand, 2-deoxyglucose, which interferes with glucose utilization, prevented the induction of maturation brought about by P5C. Apocynin and diphenyleneiodonium, inhibitors of NADPH oxidase, prevented meiotic maturation in the presence or absence of FSH. Gonadotropin-induced maturation was also prevented by 6-aminonicotinamide (6-AN) and dehydroepiandrosterone (DHEA), inhibitors of the two NADP-dependent enzymes of the PPP, and this was accompanied by suppression of glucose consumption. Phosphoribosyl-pyrophosphate (PRPP) is an important compound required in purine metabolism and can be formed from the end product of the oxidative arm of the PPP, ribose-5-phosphate. Ribose, which can be metabolized to PRPP, increased PRPP synthesis in complexes and induced meiotic maturation when added to hypoxanthine-arrested cumulus cell-enclosed oocytes in glucose-free medium in both the presence and absence of FSH. PRPP levels within complexes were also increased by glucose and FSH, but were reduced by hypoxanthine, 6-AN, and DHEA. In addition, exogenous PRPP stimulated maturation in hypoxanthine-arrested oocytes. These results support the proposition that glucose metabolism through the PPP is important in the meiotic induction mechanism and may involve the generation of PRPP that acts, at least in part, through the purine metabolizing pathways.

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Section: Discussionsupporting

confidence: 90%

Section: Resultsmentioning

confidence: 99%

Meiotic Induction in Cumulus Cell-Enclosed Mouse Oocytes: Involvement of the Pentose Phosphate Pathway1

Downs¹,

Humpherson²,

Leese³

1998

Biology of Reproduction

128

View full text Add to dashboard Cite

show abstract

“…Although the de novo pathway, in which IMP and adenylates are synthesized from ribose-5-phosphate, needs a great amount of ATP (47), the salvage pathway that synthesizes them from hypoxanthine needs less ATP (53). In addition, only 10 nmol/g tissue/h recovers ATP via the de novo pathway; thus, the resynthesis of adenine nucleotides via the salvage pathway is essential for yielding sufficient ATP recovery (54).…”

Section: Discussionmentioning

confidence: 99%

Xanthine oxidase inhibitor ameliorates postischemic renal injury in mice by promoting resynthesis of adenine nucleotides

Fujii¹,

Kubo

Miyashita³

et al. 2019

JCI Insight

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“…This view is consistent with evidence that the capacity of the oxidative pentose phosphate pathway in heart is very low compared with liver and other tissues and that maximal cardiac oxidative pentose phosphate pathway flux (generally Ͻ50 nmol⅐min Ϫ1 ⅐g dry wt Ϫ1 ) is far lower than that of glycolysis (7,28,33,34,40). Furthermore, nonoxidative pentose phosphate pathway flux between the hexose and ribose pools in the heart is likely even lower, probably not exceeding 2 nmol ⅐ min Ϫ1 ⅐ g dry wt Ϫ1 (12,30,44).…”

Section: Discussionmentioning

confidence: 99%

Accelerated rates of glycolysis in the hypertrophied heart: are they a methodological artifact?

Leong

Grist

Parsons

et al. 2002

American Journal of Physiology-Endocrinology and Metabolism

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Glycolysis, measured by (3)H(2)O production from [5-(3)H]glucose, is accelerated in isolated working hypertrophied rat hearts. However, nonglycolytic detritiation of [5-(3)H]glucose via the nonoxidative pentose phosphate pathway (PPP) could potentially lead to an overestimation of true glycolytic rates, especially in hypertrophied hearts where the PPP may be upregulated. To address this concern, we measured glycolysis using [5-(3)H]glucose and a second, independent method in isolated working hearts from halothane-anesthetized, sham-operated and aortic-constricted rats. Glycolysis was accelerated in hypertrophied hearts compared with control hearts regardless of the method used. There was also excellent concordance in glycolytic rates between the different methods. Moreover, activity of glucose-6-phosphate dehydrogenase and expression of transaldolase, enzymes controlling key steps in the oxidative and nonoxidative PPP, respectively, were not different between control and hypertrophied hearts. Thus nonglycolytic detritiation of [5-(3)H]glucose in the PPP is insignificant, and (3)H(2)O production from [5-(3)H]glucose is an accurate means to measure glycolysis in isolated working normal and hypertrophied rat hearts. Furthermore, the PPP does not appear to be increased in cardiac hypertrophy induced by abdominal aortic constriction.

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Adenine nucleotide synthesis de novo in mature rat cardiac myocytes

Cited by 12 publications

References 13 publications

Meiotic Induction in Cumulus Cell-Enclosed Mouse Oocytes: Involvement of the Pentose Phosphate Pathway1

Meiotic Induction in Cumulus Cell-Enclosed Mouse Oocytes: Involvement of the Pentose Phosphate Pathway1

Xanthine oxidase inhibitor ameliorates postischemic renal injury in mice by promoting resynthesis of adenine nucleotides

Accelerated rates of glycolysis in the hypertrophied heart: are they a methodological artifact?

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