Glucose Production by the Human Placenta in Vivo

Prendergast, C.H; Parker, KH; Gray, Robert M.; Venkatesan, S.; Bannister, Peter A.; Castro-Soares, J; Murphy, Keefe; Beard, R. W.; Regan, Lesley; Robinson, Stephen T.; Steer, Philip; Halliday, D.; Johnston, Desmond G.

doi:10.1053/plac.1999.0419

Cited by 23 publications

(7 citation statements)

References 14 publications

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“…Glucose is the primary energy substrate for the placenta and the fetus and fetoplacental glucose needs are met entirely by transfer from the maternal circulation ( 31 ). In late pregnancy GLUT1 ( SLC2A1 ) is the primary placental glucose transporter in the human ( 32 ) whereas both GLUT1 and GLUT3 ( SLC2A3) mediate placental glucose transport in the rodent ( 33 ).…”

Section: Discussionmentioning

confidence: 99%

Increased placental nutrient transport in a novel mouse model of maternal obesity with fetal overgrowth

Rosario

Kanai

Powell

et al. 2015

Obesity

105

114

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OBJECTIVETo identify possible mechanisms linking obesity in pregnancy to increased fetal adiposity and growth, we developed a unique mouse model of maternal obesity associated with fetal overgrowth and tested the hypothesis that maternal obesity causes up-regulation of placental nutrient transporter expression and activity.METHODSC57BL/6J female mice were fed a control (C) or a high fat/high sugar (HF/HS) pelleted diet supplemented by ad libitum access to sucrose (20%) solution, mated and studied at embryonic day 18.5.RESULTSHF/HS diet increased maternal fat mass by 2.2-fold (p<0.01) and resulted in glucose intolerance with normal fasting glucose. Maternal circulating insulin, leptin, and cholesterol were increased (p<0.05) whereas total and high molecular weight (HMW) adiponectin were decreased (p<0.05). HF/HS diet increased fetal weight (+18%, p=0.0005). In trophoblast plasma membrane (TPM) isolated from placentas of HF/HS fed animals, protein expression of glucose transporter (GLUT) 1 and 3, sodium-coupled neutral amino acid transporter (SNAT) 2 and large neutral amino acid transporters 1 (LAT1) was increased. TPM System A and L amino acid transporter activity was increased in the HF/HS group.CONCLUSIONUp-regulation of specific placental nutrient transporter isoforms may constitute a mechanism underlying fetal overgrowth in maternal obesity.

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Section: Discussionmentioning

confidence: 99%

Increased placental nutrient transport in a novel mouse model of maternal obesity with fetal overgrowth

Rosario

Kanai

Powell

et al. 2015

Obesity

105

114

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“…Recent studies show that GLUT3 protein is expressed as well, localized mainly in the cytotrophoblasts of the placental villi (Korgun et al 2005). The placenta itself does metabolize some glucose, either by glycolysis of the pentose phosphate shunt pathway, or for storage as glycogen (Prendergast et al 1999).…”

Section: Discussionmentioning

confidence: 99%

“…Recent studies, using glucose labeled with stable isotopes in normal pregnancies, provide evidence that the placenta is itself capable of producing glucose for fetal needs (Prendergast et al 1999).…”

Section: Discussionmentioning

confidence: 99%

In Vivo Quantification of 18f-FDG Uptake in Human Placenta During Early Pregnancy

Zanotti‐Fregonara¹,

Jan

Champion³

et al. 2009

Health Physics

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18F-FDG is the most widely used PET radiopharmaceutical. Nevertheless, no data for 18F-FDG uptake in the human placenta have been reported. We recently reported on embryo dosimetry in a woman who underwent an 18F-FDG PET/CT scan during early pregnancy. In the present work we attempt an in vivo quantification of the 18F-FDG uptake by the placenta. The 27-y-old woman received 320 MBq of 18F-FDG for a follow-up study for Hodgkin's lymphoma and was later discovered to be pregnant (embryo age = 8 wk). Imaging started 1 h after injection. The maximum placental tissue uptake (SUVmax) was 2.5. This value was conservatively attributed to the entire placental volume, i.e., 45 mL, a value representative of the average dimensions of a normal placenta at 8 wk. On the basis of these measurements, placenta 18F-FDG uptake in our patient was 0.19% of the injected activity. A Monte Carlo simulation was used to derive the photon dose to the embryo from the placenta (0.022 x 10(-2) mGy per MBq of injected 18F-FDG) and from the surrounding amniotic fluid (0.017 x 10(-2) mGy MBq(-1)). This increases our previously calculated dose (3.3 x 10(-2) mGy MBq(-1)) by only a small fraction (1.18%), which does not justify modifying the previous estimate given the overall uncertainties.

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“…The presence of G6Pase has also been detected histochemically in the syncytiotrophoblasts of the placenta [81]. Dilution of isotopically labelled glucose in the umbilical vein of the fetus as compared with maternal blood indicates production of glucose by the placenta [82].…”

Section: Tissue Distributionmentioning

confidence: 97%

The glucose-6-phosphatase system

Schaftingen¹,

Gerin²

2002

Biochemical Journal

318

205

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Glucose-6-phosphatase (G6Pase), an enzyme found mainly in the liver and the kidneys, plays the important role of providing glucose during starvation. Unlike most phosphatases acting on water-soluble compounds, it is a membrane-bound enzyme, being associated with the endoplasmic reticulum. In 1975, W. Arion and co-workers proposed a model according to which G6Pase was thought to be a rather unspecific phosphatase, with its catalytic site oriented towards the lumen of the endoplasmic reticulum [Arion, Wallin, Lange and Ballas (1975) Mol. Cell. Biochem. 6, 75–83]. Substrate would be provided to this enzyme by a translocase that is specific for glucose 6-phosphate, thereby accounting for the specificity of the phosphatase for glucose 6-phosphate in intact microsomes. Distinct transporters would allow inorganic phosphate and glucose to leave the vesicles. At variance with this substrate-transport model, other models propose that conformational changes play an important role in the properties of G6Pase. The last 10 years have witnessed important progress in our knowledge of the glucose 6-phosphate hydrolysis system. The genes encoding G6Pase and the glucose 6-phosphate translocase have been cloned and shown to be mutated in glycogen storage disease type Ia and type Ib respectively. The gene encoding a G6Pase-related protein, expressed specifically in pancreatic islets, has also been cloned. Specific potent inhibitors of G6Pase and of the glucose 6-phosphate translocase have been synthesized or isolated from micro-organisms. These as well as other findings support the model initially proposed by Arion. Much progress has also been made with regard to the regulation of the expression of G6Pase by insulin, glucocorticoids, cAMP and glucose.

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Glucose Production by the Human Placenta in Vivo

Cited by 23 publications

References 14 publications

Increased placental nutrient transport in a novel mouse model of maternal obesity with fetal overgrowth

Increased placental nutrient transport in a novel mouse model of maternal obesity with fetal overgrowth

In Vivo Quantification of 18f-FDG Uptake in Human Placenta During Early Pregnancy

The glucose-6-phosphatase system

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