Lactate and Pyruvate as Fetal Metabolic Substrates

Char, Valerie Charlton; Creasy, Robert K.

doi:10.1203/00006450-197604000-00006

Cited by 53 publications

(32 citation statements)

References 8 publications

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“…The fetus as a whole is known to be a net consumer of lactate, because there is fetal uptake of lactate from the placenta via the umbilical circulation (27). However, lactate is also produced within the fetus at high rates (28).…”

Section: Discussionmentioning

confidence: 99%

“…The umbilical G/02 ratio in the fetal sheep has been reported as 0.41 to 0.57 (8,33). This indicates that the amount of glucose taken up by the total fetus is less than the amount of substrate needed to sustain fetal energy metabolism and other metabolites such as amino acids and lactate are also used to fuel oxidative metabolism (27,31). However, several individual fetal organs take up large quantities of glucose, which totally account for or even exceed their fuel needs for oxidative metabolism.…”

Section: Discussionmentioning

confidence: 99%

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Substrate Utilization by the Fetal Sheep Lung during the Last Trimester

Simmons

Charlton

1988

Pediatr Res

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ABSTRACT. I n vivo substrate utilization has not been described for the maturing fetal lung. We, therefore, studied pulmonary delivery and use of major fetal substrates in six chronically catheterized fetal lambs over 119-141 days gestation. Oxygen, glucose, lactate, and a-amino nitrogen concentrations were measured in the pulmonary artery and pulmonary vein whereas lung blood flow was determined using labeled microspheres. We found that lung oxygen availability and use increased near term. 606Using the chronically catheterized fetal sheep model (6), we determined the availability of major fetal substrates to the developing lung and lung substrate utilization during the third trimester. Pulmonary delivery and uptake of oxygen, glucose, lactate, and a-amino nitrogen were followed over the last weeks of gestation, allowing us to define the changing pattern of pulmonary substrate availability and use that accompanies advancing gestation. METHODSSurgical preparation and recovery. Six mixed Western, breeddated, pregnant sheep of 1 15-125 days gestation were surgically prepared with indwelling catheters, using methods described previously (6). Six fetal lambs were catheterized, five singletons and one from a set of twins. Surgery was performed after the animals had fasted 24 h. Spinal anesthesia was induced with 2.0 ml of 1 % tetracaine hydrochloride and analgesia was provided with intravenous pentobarbital (65 mg/ml) as needed. Polyvinyl catheters (0.050 inch inner diameter and 0.090 inch outer diameter) were placed in the maternal femoral artery and vein. The uterus was then exposed through a midline abdominal incision and opened. Local anesthesia with 1% xylocaine was used for all fetal incisions; pentobarbital (5-10 mg/kg) and succinyl choline (1 mg/kg) were given as needed for fetal sedation and to minimize fetal movement. Catheters (0.030 inch inner diameter and 0.048 inch outer diameter) were inserted either into the fetal femoral artery and vein of one hindlimb (four animals) or into the carotid artery and jugular vein (two animals). The fetal chest was then exposed and a thoracic incision was made on the left side, from sternum to spine. The pleural space was entered through the fourth intercostal space and the lungs were gently retracted. The pericardium was opened and a 20-gauge Teflon catheter, fitted on a piece of polyvinyl tubing (7), was then placed into the main pulmonary artery. A catheter (0.01 1 inch inner diameter and 0.030 inch outer diameter) was inserted into a distal pulmonary vein and threaded up into a major vein draining the upper lobe of the left fetal lung. The fetal chest was then closed. A multipore amniotic fluid catheter was anchored in the uterus and the uterus was also sutured closed. All catheters were exteriorized through a stab wound in the maternal flank, where they were protected by a mesh pocket. At surgery, penicillin (1 million units) and kanamycin (200 mg) were given to the ewe intravenously and were also instilled into the amniotic cavity.After surgery the ewes were fed ad...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Substrate Utilization by the Fetal Sheep Lung during the Last Trimester

Simmons

Charlton

1988

Pediatr Res

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“…This study provides the first in vitro evidence for the role of lactate as an important precursor for fatty acid synthesis in adipose tissue of the bovine fetus ( dehydrogenase in both fetal and newborn calf adipose tissue appear nonlimiting and are far in excess of the sum of the rates of lactate oxidation and incorporation into triacyl glycerol (Tables 2 and 3). The importance of lactate as a major exogenous nutrient for the developing fetal lamb has been recognized (17,18). The ratios of glucose I-14C/glucose 6-I4C conversion to C02 and the calculated (see "Results") contribution of the pentose phosphate cycle to glucose metabolism indicate that metabolism of glucose via pentose phosphate cycle is increased in adipose tissue of fetal and depressed in adipose tissue of newborn calves.…”

Section: Glycerol For Fatty Acid Esterification Pentose Phosphatementioning

confidence: 99%

Glucose, Acetate, and Lactate Metabolism in Perirenal Adipose Tissue of Fetal and Newborn Calves

Wijayasinghe

1986

Pediatr Res

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ABSTRACT. Rates of utilization of glucose, acetate, and cerning such changes in lipid metabolism have yet to be obtained. lactate and activities of selected enzymes were determined The present investigation involved studies of adipose tissue from in vitro to characterize the nature of lipogenesis and me-fetal and unsuckled newborn calves. Rates of utilization of tabolite utilization in perirenal adipose tissue from 6-to 7-glucose, acetate, and lactate, as substrates for oxidation and for month old fetal and 3-to 4-h-old unsuckled newborn calves. synthesis of fatty acids and glyceride glycerol, were determined Contribution of the pentose phosphate cycle to glucose in vitro to characterize the nature of lipogenesis and patterns of metabolism was estimated using specifically labeled glu-metabolite utilization. Specifically labeled glucose was employed cose. Rates of fatty acid synthesis from all three substrates to evaluate the contribution of the pentose phosphate cycle to and oxidation of glucose were much greater in fetal than glucose metabolism and to the reducing equivalents needed for in newborn adipose tissue. In fetal adipose tissue, acetate fatty acid synthesis. In addition, activities of selected enzymes and lactate were major sources of carbon for fatty acid related to lipogenesis in adipose tissue were also assayed. synthesis; glucose functioned mainly by metabolism via the pentose phosphate cycle to provide reducing equivalents for fatty acid synthesis and by incorporation into glyceride MATERIALS AND METHODS glycerol for fatty acid esterification. Pentose phosphatePerirenal adipose tissue samples were obtained from five fetal cycle contributed 58 and 12% to glucose metabolism in calves (180-2 10 days gestation or 64-75% of full term) and eight adipose tissue of fetal and newborn calves, respectively. newborn unsuckled calves (3-4 h after birth). Newborn calves Adipose tissue metabolism of newborn calves was charac-were sacrificed by exsanguination prior to tissue removal. ~d iterized by greatly depressed rates of fatty acid synthesis pose tissue samples were placed in warn saline (37" C) for despite high enzyme activities and elevated rates of gl~cer-transport to the laboratory, cleaned of connective tissue and ide glycerol synthesis. (Pediatr Res 20: 542-544, 1986) blood vessels, and cut into small (30-50 mg) pieces. Adipose tissue pieces weighing 50-100 mg were placed in siliconized 25-ml Erlenmeyer flasks containing 2 ml of incubation medium (Table 1). Concentrations of glucose, acetate, Iactate/pyruvate, M~~~ studies of fetal metabolism have been carried out in and insulin in the incubation medium were determined in the sheep with substrate utilization usually being determined on the preliminary experiment to achieve maximum rates of substrate basis of rates of oxygen consumption and uptake of different utilization. The flasks were gassed with a mixture of 95% O2 and substrates. Various acute and chronic preparations and tech-5% C02, capped with self-sealing rubber serum caps fitted wth niques suc...

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“…Keeping in view the "AATF RNome Hysteresis Model" proposed here (Figure 3), it becomes pertinent to ask as to how the immune privilege is extended to the antigens that emerged after puberty (spermatocyte antigens), during pregnancy (fetus antigens), or during lactation (milk antigens). The answer to this question evolves from the findings that revealed: a) Breast milk is a significant endogenous source of lactic acid-bacteria as well as contains TGF-β for initiation of IgA production in new born infants [58,59]; b) Lactate acts as a fetal fuel and TGF-β has been recognized to be of major importance in the scar-less wound repair observed in fetuses [56,57]; c) Spermatocytes utilize lactate as the main source of energy [54] and TGF-β signaling pathway is necessary to maintain spermatogenesis [55]. AATF RNome exhibited "Hysteresis Model" provides cells, within human tissues, with a unique mechanism to decouple/couple the glycolysis from/ with the aerobic-respiration in a fashion that allows these cells to undergo cyclic-dedifferentiation for expressing variety of receptors having capacity to read the incoming signals as "Friend" or "Foe" and write a script for calibrated-response in order to erase the signals perceived to be "Foe" by these cells.…”

Section: Truncated Aatf Proteinmentioning

confidence: 99%

“…Aerobic-glycolysis induced by miR-2909 can also disable the immune cells by using sugar [53]. Interestingly, immune privileged organs are well known to produce TGF-β as well as lactate [54][55][56][57][58][59] and it is their this ability which not only protects these organs from pathogens but also confers these organs with the inability to reject allogenic transplants even though these organs are bathed with the warmth and nutrients of blood (the mobile-tissue). Hence miR-2909 oscillations ensure aerobic-glycolysis as the driving energysource for immune privileged organs to enable them to suppress Th1 type and DTH responses which is accompanied by increased recruitment of regulatory T-cells as well as induction of IgA classswitching.…”

Section: Cellular and Molecular Medicine: Open Access Issn 2573-5365mentioning

confidence: 99%

AATF Genome: Evolution of Allorecognition

Kaul¹

2016

Cell Mol Med

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Lactate and Pyruvate as Fetal Metabolic Substrates

Cited by 53 publications

References 8 publications

Substrate Utilization by the Fetal Sheep Lung during the Last Trimester

Substrate Utilization by the Fetal Sheep Lung during the Last Trimester

Glucose, Acetate, and Lactate Metabolism in Perirenal Adipose Tissue of Fetal and Newborn Calves

AATF Genome: Evolution of Allorecognition

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