Regulatory Role of Fructose-2,6-bisP on Glucose Metabolism in Frog Oocytes:In VivoInhibition of Glycogen Synthesis

Guixé, Victoria; Preller, Ana; Kessi, Eduardo; Ureta, Tito

doi:10.1006/abbi.1997.0360

Cited by 6 publications

(6 citation statements)

References 29 publications

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“…Though there are previous reports on the utilization of radioactive methionine and glucose in Mongolian gerbil [33] and rat [34] embryos, respectively, there is little information on fructose utilization in porcine embryos. Nonetheless, Guixe et al [35] proposed that fructose plays an important role in the utilization of 14 C-glucose in frog oocytes. Thus, in the present study, the increased incorporation of 14 C-fructose by porcine oocytes is an indicator of the increased metabolism of fructose via the glycolysis pathway.…”

Section: Discussionmentioning

confidence: 99%

The beneficial effect of fructose and glucose on in vitro maturation and the fertilization of porcine oocytes

Tsujii

Lee

Hossain

et al. 2008

Reprod Medicine & Biology

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Purpose This study was conducted to investigate the effects of supplementing fructose in the culture medium on in vitro maturation (IVM), in vitro fertilization (IVF), and metabolism of porcine oocytes. Methods Porcine oocytes were matured in vitro in modified North Carolina State University 37 medium (NCSU-37) and then supplemented with either glucose (5.5 mM), fructose (5.5 mM), or glucose (2.75 mM) plus fructose (2.75 mM). The maturation and fertilization of oocytes, and the incorporation and oxidation of 14 C-glucose, 14 Cfructose, and 14 C-methionine in oocytes at different stages of development were examined. Results The supplementation of glucose plus fructose significantly promoted (P \ 0.05) oocytes germinal vesicle break down (GVBD), maturation to metaphase II (MII), penetration by spermatozoa, and male pronuclear formation compared with glucose. The incorporation and oxidation of 14 C-methionine into the oocyte significantly increased (P \ 0.05) with glucose plus fructose supplementation than glucose. A significantly higher (P \ 0.05) rate of incorporation and oxidation was achieved with 14 Cfructose compared to 14 C-glucose. Conclusions Glucose plus fructose supplementation improved maturation, penetration by spermatozoa, male pronuclear formation, and energy metabolism by porcine oocytes.

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Section: Discussionmentioning

confidence: 99%

The beneficial effect of fructose and glucose on in vitro maturation and the fertilization of porcine oocytes

Tsujii

Lee

Hossain

et al. 2008

Reprod Medicine & Biology

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“…The key gluconeogenic enzymes phosphoenolpyruvate carboxykinase and fructose bisphosphatase are present in oocytes [4, 5]. Recently, we have reported an important role of fructose 2,6‐bisphosphate in the regulation of glucose metabolism in these cells [6].…”

Section: Introductionmentioning

confidence: 99%

In vivo operation of the pentose phosphate pathway in frog oocytes is limited by NADP⁺ availability

Preller¹,

Guixé²,

Ureta³

1999

FEBS Letters

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Evolution of CO P from labelled glucose microinjected into frog oocytes in vivo may be ascribed to the pentose-P pathway, as measured by radioactive CO P production from [1-IR C] and [6-IR C]glucose. Coinjection of NADP + and [ IR C]glucose significantly stimulated IR CO P production. The effect depends on the amount of NADP + injected, half maximal stimulation being obtained at 0.13 mM. The increase in CO P production was also observed with microinjected glucose-1-P, glucose-6-P or fructose-6-P used as substrates.

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“…A similar result was obtained by injection of 2-mercaptopicolinate (inhibitor of phosphoenolpyruvat e carboxykinase ). These observations indicate that, at low glucose concentrations, glycogen synthesis proceeds through an "indirect" pathway involving prior conversion of glucose to lactate followed by the resynthesis through gluconeogenesis of the proximate precursors of polysaccharide deposition (5,6).…”

Section: Two Pathways For Glycogen Synthesis In Frog Oocytesmentioning

confidence: 93%

Frog Oocytes: A Living Test Tube for Studies on Metabolic Regulation

Ureta

Preller²,

Kessi³

2001

IUBMB Life

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This review is intended to illustrate how live frog oocytes may be advantageously used to address the study of some problems of in vivo glucose metabolism. Glucose microinjected into the cells is preferentially committed to glycogen synthesis. We present evidence showing that both the direct and indirect pathways for polysaccharide deposition are operative in oocytes. A small amount of the injected glucose (<5%) is released as labeled CO2 mainly through the pentose-P pathway. Coinjection of NADP+ and glucose significantly stimulates 14CO2 production, half-maximal stimulation being obtained at 0.13 mM. Finally, we show the use of frog oocytes to measure in vivo the control coefficient of hexokinase on glycogen synthesis and the pentose-P pathway. A value of 0.7 was found for the control coefficient of hexokinase on glycogen synthesis, while the enzyme has no control at all over the pentose-P pathway. Therefore, the frog oocyte may be used as a living test tube for the study of almost any metabolic process of interest.

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Regulatory Role of Fructose-2,6-bisP on Glucose Metabolism in Frog Oocytes:In VivoInhibition of Glycogen Synthesis

Cited by 6 publications

References 29 publications

The beneficial effect of fructose and glucose on in vitro maturation and the fertilization of porcine oocytes

The beneficial effect of fructose and glucose on in vitro maturation and the fertilization of porcine oocytes

In vivo operation of the pentose phosphate pathway in frog oocytes is limited by NADP⁺ availability

Frog Oocytes: A Living Test Tube for Studies on Metabolic Regulation

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Regulatory Role of Fructose-2,6-bisP on Glucose Metabolism in Frog Oocytes:In VivoInhibition of Glycogen Synthesis

Cited by 6 publications

References 29 publications

The beneficial effect of fructose and glucose on in vitro maturation and the fertilization of porcine oocytes

The beneficial effect of fructose and glucose on in vitro maturation and the fertilization of porcine oocytes

In vivo operation of the pentose phosphate pathway in frog oocytes is limited by NADP+ availability

Frog Oocytes: A Living Test Tube for Studies on Metabolic Regulation

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Product

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In vivo operation of the pentose phosphate pathway in frog oocytes is limited by NADP⁺ availability