Glucose/Oxygen Quotients across the Hindlimb of Fetal Lambs

Morriss, Frank H.; Boyd, Robert D.; Makowski, Edgar L.; Meschia, G; Battaglia, Frederick C.

doi:10.1203/00006450-197310000-00002

Cited by 13 publications

(5 citation statements)

References 7 publications

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“…Furthermore, catheters were placed, minimizing surgical manipulation of the study limb, and venous samples drawn at rates less than 5 ml/min in order to avoid retrograde venous sampling. As a result, there was less variability observed in the oxygen, glucose and lactate data compared with results reported previously [6,8].…”

Section: Discussionsupporting

confidence: 41%

“…The mean values reported for the fetal hindlimb glucose/oxygen quotient under normal conditions vary between 0.82 [6] and 1.06 [8], suggesting that most of the substrate requirement for oxidative metabolism can be met by glucose. Therefore, an insulininduced increase in glucose uptake by the hindlimb tissues of the fetus may not be directed toward oxidative metabolism as is presumed to be the case in the hindlimb tis sues of the adult when stimulated with insu lin [7],…”

Section: Introductionmentioning

confidence: 99%

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Effect of Insulin on Glucose/Oxygen and Lactate/Oxygen Quotients across the Hindlimb of Fetal Lambs

Wilkening¹,

Molina²,

Battaglia³

et al. 1987

Neonatology

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In order to determine whether insulin stimulates glucose uptake by the hindlimb tissue of the fetal lamb, we performed 7 paired, euglycemic glucose ‘clamp’ experiments in 7 chronically prepared fetal sheep. Four sample sets for oxygen content, glucose and lactate concentration were drawn from the external iliac artery and vein during a control period and repeated during a euglycemic, hyperinsulinemic ‘clamp’ period. Insulin was infused at constant rate (4 mU/min/kg) and the fetal arterial glucose concentration was maintained by variable glucose infusion. The glucose/oxygen quotient increased significantly: 1.05 ± 0.07 (control) versus 2.02 ± 0.16 (hyperinsulinemia). There was no change in lactate/oxygen quotient. The data demonstrate that with maximal insulin stimulation, fetal hindlimb tissues increase glucose uptake by 92% with no large change in lactate production, indicating a net accumulation of glucose carbon under these experimental conditions.

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Section: Discussionsupporting

confidence: 41%

Section: Introductionmentioning

confidence: 99%

Effect of Insulin on Glucose/Oxygen and Lactate/Oxygen Quotients across the Hindlimb of Fetal Lambs

Wilkening¹,

Molina²,

Battaglia³

et al. 1987

Neonatology

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“…In the human and sheep, glycerol doesn't cross the placenta rapidly (Sabata et at., 1968 ;Schreiner et al, 1978 Meschia, 1973, 1978 ;Silver, 1976 (Silver, 1976 (Williamson, 1975 ;Bailey and Lockwood, 1973). As pregnant rats and women develop a marked ketonemia during a short term starvation (Freinkel et al, 1972 ;Felig, 1973), the utilization of ketone bodies as an alternative fuel in the placenta and various fetal tissues (Shambaugh et al, 1977a, b) (Morriss et al, 1973 ;Jones et al, 1975 (Warnes ef al., 1977a ;Prior and Christenson, 1977 ;Hodgson and Mellor, 1977). The values reported (7.4, 7.6 and 8.4 mg.min-l .kg-1 ) are approximately twice the umbilical uptake of glucose Meschia, 1973, 1978 .…”

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confidence: 99%

Fuel metabolism in the mammalian fetus

Girard¹,

Pintado²,

Ferré³

1979

Ann. Biol. anim. Bioch. Biophys.

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Summary. The mammalian fetus receives energy fuels from its mother through the placenta. The (Freinkel et al., 1971(Freinkel et al., , 1972(Freinkel et al., , 1974 Knopp, 1978) and the principal results will be summarized briefly.Adaptation of maternal fuel metabolism to fetal growth.During gestation, the increased food intake by the pregnant mother contributes to a steady weight gain. This weight gain has 2 main components which accumulate at different times in gestation. During the first and second part of gestation the mother accumulates fat stores (Beaton et al., 1954 ;Hytten and Leicht, 1971) In all the species studied, the fetal blood glucose levels are lower than the maternal levels, but they are directly correlated with the maternal levels over a wide range of concentrations Shelley, 1973 ;Silver, 1976 (Haour and Bertrand, 1974 ;Marshall et al., 1974 ;Posner, 1975).In most of the species studied, fetal lactate concentration is 2 or 3 fold higher than maternal lactate concentration (table 1) Char and Creasy, 1976a ;Silver, 1976). High rates of lactate production by the placenta, under aerobic conditions in vitro, have also been found in rat and man. The rate of placental lactate production is closely related to the rate of glucose utilization by the placenta.In several species (sheep, goat, cow, pig and horse) a part of glucose (10 p. 100) taken up by the placenta is converted into fructose which is transferred to the fetus. Fructose is present in very high concentration in the blood of the fetus of those species but is absent from maternal blood, since it is not passed back to the mother. When the mother is in the fed state, there is no evidence for utilization of fructose by the fetus. However, during maternal starvation, a small but significant utilization by the sheep fetus has been shown (Schreiner et al., 1978). This suggests that fructose may be a carbohydrate store, as glycogen, which could be used in situation of emergency by the fetus.2) Amino acids.The level of amino acids is 2 to 3 fold higher in the fetal blood than in the maternal blood (table 1). The amino acids are concentrated by the placenta and released to the fetus against a concentration gradient, by an active transport mechanism (review in Young and Hill, 1973). In the sheep (Lemons et al., 1976) fetal uptake of glutamine, branched chain amino-acids, arginine, phenylalanine and tyrosine is in excess of estimated growth requirements, suggesting that they are used for other purposes than protein synthesis. In the rat, fetal uptake of glutamine has also been found to be much higher than for other amino-acids (Yamamoto et al.,1974). This will be discussed later.3) Free fatty acids.In (Char and Creasy, 19766). In the cow and guinea-pig a significant umbilical uptake of acetate has been shown, and it is dependant upon maternal acetate concentration (Silver, 1976 ;Jones, 1976a). 4) Ketone bodies.Ketone bodies are readily transferred from the mother to the fetus in human and rat (Sabata et al., 1968 ;Scow et al., 1958), and there is a c...

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“…Skeletal muscle, on the other hand, exhib ited a substantial output of lactate even in the normoxic situation, as documented earlier [27,28]. The lactate release ceased first in combination with very severe hypoxia ( fig.…”

Section: Discussionmentioning

confidence: 64%

Contribution of Heart Muscle, Liver, Skeletal Muscle and Placenta to the Asphyxial Hypoxanthine Elevation in the Acutely Exteriorised Fetal Lamb

Thiringer¹,

Karlsson²,

Rosén³

et al. 1984

Neonatology

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The metabolic response to different degrees of hypoxia was studied in 14 lamb fetuses. We have previously found a substantial rise in the fetal arterial plasma hypoxanthine (HX) level, in parallel with alterations of other hypoxia indices during induced asphyxia. Measurements of the arterio-venous (A-V) difference in the HX level across the CNS demonstrated a late efflux of this substance from the fetal brain, with a high resistance to asphyxia. In this study, the effluxes of HX, lactate, and in some cases glucose, from the myocardium, liver, hindleg (skeletal muscle) and placenta were investigated in acutely exteriorised sheep fetuses with graded asphyxia. The main findings were as follows: (a) myocardium: a release of HX early during asphyxia, the magnitude of which paralelled the amount of mechanical work performed by the heart; a significant lactate influx into the heart during normoxia and recovery period; (b) liver: hepatic HX release even during normoxia, increasing to substantial amounts in connection with increasing asphyxia; (c) hindleg: release of HX only during the recovery period; lactate efflux during all periods apart from severe asphyxia, when an influx was seen for both substances; (d) placenta: production of lactate during normoxia, and an efficient clearance of both lactate and HX from the fetal plasma in combination with their concentration increasing during asphyxia. It is concluded that the myocardium and liver are the main contributors to the elevated HX level during fetal asphyxia among the fetal organs investigated, while skeletal muscle releases HX mostly during the period of reoxygenation.

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Glucose/Oxygen Quotients across the Hindlimb of Fetal Lambs

Cited by 13 publications

References 7 publications

Effect of Insulin on Glucose/Oxygen and Lactate/Oxygen Quotients across the Hindlimb of Fetal Lambs

Effect of Insulin on Glucose/Oxygen and Lactate/Oxygen Quotients across the Hindlimb of Fetal Lambs

Fuel metabolism in the mammalian fetus

Contribution of Heart Muscle, Liver, Skeletal Muscle and Placenta to the Asphyxial Hypoxanthine Elevation in the Acutely Exteriorised Fetal Lamb

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