Fetal glucose uptake and utilization as functions of maternal glucose concentration

Hay, William W.; Sparks, John W.; Wilkening, Randall B.; Battaglia, F. C.; Meschia, Giacomo

doi:10.1152/ajpendo.1984.246.3.e237

Cited by 75 publications

(70 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As a consequence of the hyperglycaemia induced by meal intake in the sow, we observed an elevation of foetal glycaemia, since the placental transfer of glucose depends on the concentration difference of glucose between the mother and the foetus [3]. The slope of the relationship between maternal and foetal plasma glucose averaged about 0.29 which was in the same range with that reported in sheep (0.32, Philipps et al [41]; 0.38, Hay et al [28]). …”

Section: Glycerolsupporting

confidence: 76%

“…This could be partly explained by a lack of knowledge regarding the transfer of nutrients from the mother to the foetus, as well as the control of foetal nutrient utilisation. Due to technical difficulties, these studies were undertaken in species in which the females carry foetuses of large size and which are also less prone to abortion such as the cow [8] and sheep [28,29]. Some information has also been gained in smaller species like rabbits [24], guinea pigs [57,58] or rats [23], using labelled substrates.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effects of meal intake on materno-foetal exchanges of energetic substrates in the pig

Père

2001

Reprod. Nutr. Dev.

View full text Add to dashboard Cite

-Catheters were implanted in 18 gilts at 99 days of pregnancy to study the effects of meal intake on uterine and umbilical uptake of energetic substrates in the conscious pig. Blood samples were withdrawn at 105 days of pregnancy from 10 min before and up to 90 min after feeding of a 2.5-kg meal. Plasma glucose was 2.2 to 2.5 times lower and blood lactate 2 to 3 times higher in the foetus than in the sow. Glucose and lactate increased after the meal. Their umbilical uptake amounted to 0.32 and 0.26 mmol . L -1 , respectively. Fructose was found in large amounts in foetal plasma (4.3 mmol . L -1 ), but it did not seem to be metabolised by the foetus. Meal intake decreased plasma levels of FFA and glycerol in the sows, whereas they increased in the foetuses. A small FFA and glycerol umbilical uptake was recorded (14 and 6 µmol . L -1 , respectively). Most features of the maternofoetal exchanges in the porcine species resemble those of other species, especially ruminants. materno-foetal exchange / energetic substrate / meal intake / pig Résumé -Effets de la prise alimentaire sur les échanges materno-foetaux de substrats énergétiques chez le porc. Des cathéters ont été implantés sur 18 truies à 99 jours de gestation afin d'étudier chez l'animal vigile les effets d'une prise alimentaire sur la capture de substrats énergétiques par l'utérus et le foetus. Des échantillons de sang ont été prélevés à 105 jours de gestation entre 10 min avant et 90 min après la distribution d'un repas de 2,5 kg. La glycémie était 2,2 à 2,5 fois plus faible et la lactatémie 2 à 3 fois plus élevée chez le foetus que chez la mère. Elles augmentaient après le repas. La capture de glucose et de lactate par le foetus était respectivement de 0,32 et 0,26 mmol . L -1 . Les concentrations sanguines de fructose étaient élevées chez le foetus (4,3 mmol . L -1 ), mais ce substrat ne semblait pas métabolisé. La consommation du repas provoquait une diminution des teneurs plasmatiques en AGL et en glycérol des truies alors qu'elles augmentaient chez les foetus. Une faible Reprod. Nutr. Dev. 41 (2001) 285-296 285

show abstract

Section: Glycerolsupporting

confidence: 76%

Section: Introductionmentioning

confidence: 99%

Effects of meal intake on materno-foetal exchanges of energetic substrates in the pig

Père

2001

Reprod. Nutr. Dev.

View full text Add to dashboard Cite

show abstract

“…The prime dose of radioactive glucose was estimated according to an assumed tracer glucose distribution space of 70% of fetal weight, based on bolus tracer experiments (12) and on preliminary trials in our laboratory. This primed, constant infusion method has been shown to produce a constant specific activity in the fetus after 60-75 rnin of infusion (5,7,9). Between 90 and 120 rnin of tracer infusion (control sampling period), four sets of simultaneous umbilical venous and arterial blood samples were withdrawn at 10-min intervals for glucose concentration, radioactive glucose concentration, radioactive carbon dioxide concentration, oxygen content, and antipyrine concentration.…”

Section: Methodsmentioning

confidence: 99%

Effects of Insulin and Glucose Concentrations on Glucose Utilization in Fetal Sheep

Hay¹,

Meznarich²,

DiGiacomo³

et al. 1988

Pediatr Res

View full text Add to dashboard Cite

ABSTRACT. Glucose and insulin clamp experiments were performed in vivo in chronically catheterized, late-gestation fetal lambs to quantify the effects of glucose and insulin on fetal glucose metabolism. Fetal glucose uptake from the placenta via the umbilical circulation (umbilical glucose uptake) was measured by application of the Fick principle, and fetal glucose utilization rate (GUR) was measured using [U-'4C]glucose tracer. Fetal plasma insulin concentrations ranged from 2 to 119 fiU.ml-' and fetal blood glucose concentrations ranged from 7.3 to 62.6 mg.dl-I. GUR varied from 2.82 to 15.12 mg/min/kg and the exogenous glucose entry rate (umbilical glucose uptake + glu- tration and plasma insulin concentration of 20.6 mg/dl and 10 wU/ml, respectively. According to this model, the glucose and insulin effects were additive. Furthermore, change in GUR was not proportionate to change in glucose concentration, accounting for a decreasing metabolic clearance rate at higher glucose concentrations. These results demonstrate the three-dimensional nature of the simultaneous additive effects of glucose and insulin on glucose utilization. These results also serve to emphasize that comparative studies of insulin and glucose metabolism in fetal lambs must be conducted at similar concentrations of glucose to avoid inaccurate estimates of the magnitude of insulin effect on glucose metabolism. (Pediatr Res 23: 381-387, 1988) Abbreviations 38Recently, we demonstrated that the maximum response of the fetal lamb to insulin infusion was a doubling of fetal glucose utilization rate (4). These studies were camed out using a glucose clamp technique in which individual fetuses were studied at "euglycemia," defined as the control (preinsulin) level of glucose. These glucose concentrations covered the normal range of glucose concentrations for well-fed Columbia-Rambouillet sheep, 15-25 mg/dl whole blood. Over this range of glucose concentration, glucose utilization rate was positively correlated with glucose concentration both at normal and high levels of insulin. These results strongly suggested that ovine fetal glucose metabolism could be more fully characterized according to effects of both insulin and glucose concentrations. To date, however, there has been little direct experimental evidence provided to complete such characterization of fetal insulin and glucose effects. As a result, the response of fetal glucose metabolism to changes of fetal glycemia and fetal insulinemia, produced by changes in maternal glucose concentration that occur with important clinical problems such as diabetes mellitus or fasting-induced hypoglycemia, have not been adequately quantified.Therefore, the present studies were conducted to measure glucose metabolism in the fetal lamb at different levels of plasma insulin and blood glucose concentration in order to provide a more complete description of how insulin and glucose act together to regulate fetal glucose metabolism. In these studies, glucose and insulin clamp experiments were performed in vivo i...

show abstract

“…Therefore, it has been ignored in studies of metabolic pathways associated with metabolism of hexose sugars, because glucose, but not fructose, is metabolized via the glycolytic pathway (16)(17)(18)(19)(20). Nevertheless, fructose can be used for synthesis of nucleic acids and generation of reducing equivalents in the form of NADPH H + in the fetal pig (21) and in HeLa cells (22).…”

mentioning

confidence: 99%

Functional roles of fructose

Kim

Song

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

During the periimplantation period of pregnancy, pig blastocysts undergo morphological changes and differentiation requiring secretion and transport of nutrients (histotroph) into the uterine lumen. Of these nutrients, glucose is converted to fructose, an isomer of glucose, by conceptus trophectoderm. Although glucose is an energy source for proliferation and growth of mammalian cells, the role of fructose in uterine histotroph is unclear although it is the most abundant hexose sugar in fetal blood and fluids of ungulate mammals (e.g., cows, sheep, and pigs). In this study, we used porcine trophectoderm cells to determine that fructose increased cell proliferation, as did glucose. Western blot analyses of porcine trophectoderm cell extracts revealed that fructose increased the abundance of phosphorylated-RPS6K, -EIF4EBP1, and -RPS6 over basal levels within 30 min, and those levels remained elevated to 120 min. Phosphorylation of both RPS6K and EIF4EBP1 proteins in response to fructose was inhibited by inhibitors of both PI3K and MTOR. Further, when we investigated the inhibition of glutamine-fructose-6-phosphate transaminase 1 (GFPT1) by azaserine (an inhibitor of GFPT1) and GFPT1 siRNA, we found that MTOR-RPS6K and MTOR-EIF4EBP1 signaling in response to fructose is mediated via GFPT1 activation and the hexosamine pathway. We further demonstrated that fructose stimulates the production of hyaluronic acid via GFPT1 and the hexosamine biosynthesis pathway. Collectively, these results demonstrate critical roles for fructose that are mediated via the hexosamine biosynthesis pathway to stimulate MTOR cell signaling, proliferation of porcine trophectoderm cells, and synthesis of hyaluronic acid, a significant glycosaminoglycan in the pregnant uterus.trophoblast | glycosaminoglycans D omestic livestock species are invaluable animal models used extensively in research relevant to human and veterinary reproductive medicine as well as basic biological and biomedical sciences (1, 2). In particular, the ewe is an established animal model for studies of intrauterine growth restriction during fetal life that is a predisposition for the adult onset of metabolic disease (3). Ewes have a protracted periimplantation period of pregnancy, a relatively short period of gestation, and are well suited for metabolic studies to assess temporal and cell-specific changes in gene expression in response to various hormones, growth factors, and nutrients that are relevant to human and veterinary medicine and basic aspects of reproductive biology. Although fructose clearly is the major hexose sugar in fetal blood and fetal fluids of ungulate species such as sheep and pigs, it is largely ignored with respect to function because it is not metabolized via the glycolytic pathway or the Krebs cycle as an energy source. Here we provide evidence that fructose affects multiple metabolic pathways critical to pregnancy and metabolism in multiple organ systems.Fructose is the most abundant hexose sugar in fetal fluids of ungulate mammals (4-6). Fructose ...

show abstract

Fetal glucose uptake and utilization as functions of maternal glucose concentration

Cited by 75 publications

References 11 publications

Effects of meal intake on materno-foetal exchanges of energetic substrates in the pig

Effects of meal intake on materno-foetal exchanges of energetic substrates in the pig

Effects of Insulin and Glucose Concentrations on Glucose Utilization in Fetal Sheep

Functional roles of fructose

Contact Info

Product

Resources

About