The effect of fetal thyroparathyroidectomy on the transport of calcium across the ovine placenta to the fetus

Uterine and umbilical uptakes of plasma amino acids were measured simultaneously in eighteen singleton pregnant ewes at 130 ± 1 days gestation for the purpose of establishing which amino acids are produced or used by the uteroplacenta under normal physiological conditions and at what rates. The branched-chain amino acids (BCAA) had uterine uptakes significantly greater than umbilical uptakes. Net uteroplacental BCAA utilization was 8.0 ± 2.5 μmol ⋅ kg fetus−1 ⋅ min−1( P < 0.005) and represented 42% of the total BCAA utilization by fetus plus uteroplacenta. There was placental uptake of fetal glutamate (4.2 ± 0.3 μmol ⋅ kg fetus−1 ⋅ min−1, P < 0.001) and no uterine uptake of maternal glutamate. Umbilical uptake of glutamine was ∼61% greater than uterine uptake, thus demonstrating net uteroplacental glutamine production of 2.2 ± 0.9 μmol ⋅ kg fetus−1 ⋅ min−1( P < 0.021). In conjunction with other evidence, these data indicate rapid placental metabolism of glutamate, which is in part supplied by the fetus and in part produced locally via BCAA transamination. Most of the glutamate is oxidized, and some is used to synthesize glutamine, which is delivered to the fetus. There was net uteroplacental utilization of maternal serine and umbilical uptake of glycine produced by the placenta. Maternal serine utilization and glycine umbilical uptake were virtually equal (3.14 ± 0.50 vs. 3.10 ± 0.46 μmol ⋅ kg fetus−1 ⋅ min−1). This evidence supports the conclusion that the ovine placenta converts large quantities of maternal serine into fetal glycine.

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Glucose and lactate metabolism in vivo in ovine fetus

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1980.239.3.e208 ◽

1980 ◽

Vol 239 (3) ◽

pp. E208-E214 ◽

Cited By ~ 1

Author(s):

R. L. Prior

Keyword(s):

Specific Activity ◽

Maternal Plasma ◽

Fetal Weight ◽

Plasma Lactate ◽

Fetal Plasma ◽

Lactate Turnover ◽

Ovine Placenta ◽

Brachial Vein ◽

Ovine Fetus

The metabolism of glucose and lactate by the ovine fetus (123-128 days of gestation) was studied; a primed, continuous infusion of [2-3H]glucose and [U-14C]lactate into the brachial vein of six fetuses was used. Fetal plasma lactate concentrations averaged 2.12 +/- 0.25 mM and glucose concentrations averaged 9.3 +/- 1.3 mg/100 ml. Total plasma turnover of lactate was 5.22 +/- 0.7 nmol/h and that of glucose was 3.48 +/- 0.63 nmol x h-1 x kg fetal weight-1. Lactate was converted to glucose at a rate of 1.35 +/- 0.64 mmol x h-1 x kg fetal weight-1, which represented 21.6 +/- 6.0% of the lactate turnover. The percentage of glucose coming from lactate was 48.9 +/- 15.2. The specific activity of maternal plasma glucose was less than 4% of the specific activity of glucose observed in fetal plasma. No radioactivity could be detected in maternal plasma lactate. The data show that the ovine fetus or the fetal-placental unit can convert lactate to glucose by days 123-128 of gestation. A general model presented describes carbohydrate metabolism in the ovine placenta and fetus.

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PSII-35 Melatonin supplementation and restricted nutrition do not affect chorionic somatomammotropin (CSH) concentration in ovine placenta from mid- to late- gestation

Journal of Animal Science ◽

10.1093/jas/skz258.496 ◽

2019 ◽

Vol 97 (Supplement_3) ◽

pp. 244-244

Author(s):

Hanaa Mansour ◽

Caleb O Lemley ◽

Russell Anthony ◽

Kendall C Swanson ◽

Anna T Grazul-Bilska ◽

...

Keyword(s):

Histological Analysis ◽

Late Gestation ◽

Fetal Membrane ◽

Nutrient Restriction ◽

Binucleate Cells ◽

Tissue Sections ◽

Vasoactive Factors ◽

Ovine Placenta ◽

Chorionic Somatomammotropin ◽

Texas Red

Abstract Melatonin plays a role as a vasodilator. Vasoactive and angiogenic factors are expressed by placental binucleate cells (BNC) and produce chorionic somatomammotropin (CSH), known to impact fetal and placental growth. We hypothesized that melatonin supplementation and restricted nutrition from mid- to late-gestation would alter CSH concentration and some characteristics of BNC in placenta. At day 50 of gestation, ewes carrying singletons were randomly assigned to a 2 × 2 factorial design and were fed either an adequate (ADQ; 100% NRC; n = 15) or restricted (RES; 60% NRC; n = 15) diet supplemented with 0 (CON, n = 14) or 5 mg of melatonin (MEL; n = 16). Placentomes were collected on day 130 of gestation and preserved in formalin for histological analysis. Cotyledon (COT) were snap frozen for western immunoblotting analyses. Tissue sections were stained using biotinylated Dolichos Biflurus (DBA; a marker of fetal membrane) lectin and fluorescein labeled Texas red-avidin and fluorescein labeled Griffonia Simplifolica (BS) lectin (a marker of BNC). The number, area, and diameter of BNC in COT were determined by image analysis. For immunoblotting, protein was extracted from COT in SDS phosphate buffer, loaded equally, and separated on 12.5% polyacrylamide gels. Protein was transferred to PVDF membranes and incubated with rabbit anti-CSH. Bands were visualized and imaged. Data were analyzed using Proc Mixed procedure of SAS. Melatonin supplementation and restricted nutrition did not affect BNC number, area, or diameter, or CSH protein expression. While we reject our hypothesis that melatonin supplementation and nutrient restriction would alter the CSH concentration and BNC characteristics in COT, we continue to evaluate if the BNC produce angiogenic or vasoactive factors that may influence placental and mammary gland functions in sheep.

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EFFECT OF SOMATOSTATIN ON THE CONCENTRATION OF GROWTH HORMONE IN THE PLASMA OF FOETAL SHEEP

Journal of Endocrinology ◽

10.1677/joe.0.0780453 ◽

1978 ◽

Vol 78 (3) ◽

pp. 453-454 ◽

Cited By ~ 5

Author(s):

I. C. McMILLEN ◽

G. JENKIN ◽

G. D. THORBURN ◽

J. S. ROBINSON

Keyword(s):

Growth Hormone ◽

Pituitary Gland ◽

Medical Research ◽

Pituitary Stalk ◽

Obstetrics And Gynaecology ◽

Nuffield Department ◽

John Radcliffe Hospital ◽

Ovine Placenta

Nuffield Institute for Medical Research and Nuffield Department of Obstetrics and Gynaecology, John Radcliffe Hospital, Headington, Oxford, 0X3 9DU (Received 6 April 1978) Growth hormone (GH) has been located in the ovine foetal pituitary gland by day 50 of gestation (Stokes & Boda, 1968). The concentration of GH in the plasma of foetal sheep is ten times higher than the postnatal value, increasing from 40 ng/ml on day 100 of gestation to 100–120 ng/ml on day 140 (Bassett, Thorburn & Wallace, 1970). After foetal hypophysectomy, the concentration of GH falls to < 2 ng/ml, indicating that it originates in the foetal pituitary gland (Wallace, Stacey & Thorburn, 1973). Labelled GH does not cross the ovine placenta (Wallace et al. 1973). After sectioning the foetal pituitary stalk, the concentration of GH in the foetal plasma drops to approximately 5 ng/ml (Wallace et al. 1973), which implies that the secretion of GH

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