Uterine blood flow and substrate uptake in conscious rabbit during late gestation

The aim of this study was the quantitation of the metabolic demands of the uterus in rabbits between days 24 and 30 of gestation, a time at which there is a fourfold increase in fetal weight. Serial measurements of substrate concentrations in maternal artery and uterine vein were performed over this period. Uterine blood flow was measured on days 24 and 30. Uterine substrate uptake was calculated by application of the Fick principle. Over the gestation range studied, the absolute uterine blood flow increased proportionally to the uterine weight gain. The uterine arteriovenous differences for glucose (G), lactate (L), free fatty acids (FFA), ketone bodies (KB), and oxygen (O2) were constant throughout the study. At both gestational ages, the weight-specific uterine substrate consumption (G, FFA, KB, O2) and production (L) were respectively similar. On days 24 and 30 the amount of G directed to the gravid uterus represented approximately 13 and approximately 36% of the maternal glucose turnover rate, respectively. The maximum contributions of G and FFA to the uterine oxygen consumption on day 24 were 80 and 30%, respectively. We have thus confirmed that at term the gravid uterus is a site of high glucose consumption. Finally, we demonstrated that in a nonruminant species, FFA would be a substantial source of carbon.

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Transplacental clearance and blood flows of bovine gravid uterus at several stages of gestation

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1987.253.5.r735 ◽

1987 ◽

Vol 253 (5) ◽

pp. R735-R739 ◽

Cited By ~ 5

Author(s):

L. P. Reynolds ◽

C. L. Ferrell

Keyword(s):

Blood Flow ◽

Statistical Model ◽

Deuterium Oxide ◽

Gravid Uterus ◽

Uterine Blood Flow ◽

Blood Flows ◽

Bovine Placenta ◽

Umbilical Blood ◽

Placental Blood ◽

Umbilical Blood Flow

Rates of uterine and umbilical blood flows and transplacental clearance of deuterium oxide (D2O) were determined for cows on 137 +/- 1.0 (SE, n = 9), 180 +/- 0.5 (n = 8), 226 +/- 0.4 (n = 9), and 250 +/- 1.8 (n = 5) days of gestation. From days 137 to 250, rates increased 4.5-fold for uterine blood flow, 21-fold for umbilical blood flow, and 14-fold for clearance of D2O. Changes in rates of umbilical blood flow and D2O clearance paralleled increased rates of fetal growth and metabolism, which have previously been reported to occur during the last half of gestation. The regressions of D2O clearance on uterine and umbilical blood flows were significant (P less than 0.01) and explained 94-99% of the variation in placental clearance of D2O. Because the rate of D2O clearance was always less than that of uterine and umbilical blood flows, and because a relatively simple statistical model explained most of the variation in clearance, it was suggested that a concurrent or countercurrent arrangement of maternal and fetal placental microvasculatures is not adequate to explain clearance of highly diffusable substances across the bovine placenta. In addition, a placental exchange diagram of the data showed the existence of severe uneven distribution of maternal and fetal placental blood flows and/or significant shunting of maternal and fetal placental flows away from areas of exchange. Taken together, these data indicate that the placenta of the cow, like those of the sheep and goat, represents a relatively inefficient system of transplacental exchange.

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487 Effect of melatonin supplementation during mid- to late-gestation on maternal uterine blood flow and calf size at birth

Journal of Animal Science ◽

10.2527/asasann.2017.487 ◽

2017 ◽

Vol 95 (suppl_4) ◽

pp. 238-238

Author(s):

K. J. McCarty ◽

M. P. T. Owen ◽

C. G. Hart ◽

K. C. Yankey ◽

R. C. Thompson ◽

...

Keyword(s):

Blood Flow ◽

Late Gestation ◽

Uterine Blood Flow ◽

Size At Birth

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Oxygen, glucose, and lactate uptake by fetus and placenta during prolonged hypoxemia

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1995.268.2.r303 ◽

1995 ◽

Vol 268 (2) ◽

pp. R303-R309 ◽

Cited By ~ 5

Author(s):

S. B. Hooper ◽

D. W. Walker ◽

R. Harding

Keyword(s):

Blood Flow ◽

Glucose Uptake ◽

Lactate Clearance ◽

Gravid Uterus ◽

Uterine Blood Flow ◽

Fetal Circulation ◽

Umbilical Blood ◽

Pregnant Sheep ◽

Lactate Uptake ◽

Arterial O2 Saturation

Our aim was to compare the effects of short (4 h) and prolonged (24 h) periods of reduced uterine blood flow (RUBF) on fetal and placental uptake of O2, glucose, and lactate. In pregnant sheep, uterine and umbilical blood flows were measured under normal conditions and after 4 and 24 h of RUBF. A 50% reduction in uterine blood flow caused a 56% reduction in fetal arterial O2 saturation (SaO2). Umbilical blood flow increased from 325 +/- 33 to 378 +/- 32 ml.min-1.kg-1 (P < 0.05) after 4 h but was not different from pre-RUBF values after 24 h. O2 uptake by the gravid uterus was not altered by RUBF, due to an increase (84%) in uterine O2 extraction. Similarly, uteroplacental and fetal O2 consumptions and fetal glucose uptake were not affected by RUBF, whereas uteroplacental glucose uptake was significantly reduced after 4 h (by 42%) and 24 h (by 58%) of RUBF. Fetal lactate uptake was greatly reduced from 78.7 +/- 15.5 to -167 +/- 57 mumol.min-1.kg-1 after 4 h and to -198 +/- 80 mumol.min-1.kg-1 after 24 h of RUBF; negative values indicate placental lactate uptake from the fetal circulation. Thus, although RUBF significantly reduced fetal SaO2, fetal and uteroplacental O2 consumptions did not change. In addition, although fetal glucose uptake was not altered by RUBF, during RUBF the placenta became a major site of lactate clearance from the fetal circulation.

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249 Effects of Maternal Nutrient Restriction During Late Gestation on Uterine Blood Flow and Placental Size in the Primiparous Bovine Dam

Journal of Animal Science ◽

10.1093/jas/skab235.235 ◽

2021 ◽

Vol 99 (Supplement_3) ◽

pp. 129-129

Author(s):

Colby A Redifer ◽

Lindsey G Wichman ◽

Allison M Meyer

Keyword(s):

Heart Rate ◽

Blood Flow ◽

Repeated Measures ◽

Fixed Effects ◽

Color Doppler ◽

Placental Weight ◽

Late Gestation ◽

Nutrient Restriction ◽

Uterine Blood Flow ◽

Pre Treatment

Abstract To determine effects of late gestational maternal nutrient restriction (NR) on uteroplacental blood flow and placental growth, primiparous fall-calving crossbred beef heifers [BW: 451 ± 28 (SD) kg; BCS: 5.4 ± 0.7] were individually-fed either 100% (control; CON; n = 12) or 70% (n = 13) of energy and protein requirements for maintenance, pregnancy, and growth during the last 120 days of gestation. Transrectal color Doppler ultrasonography of both uterine arteries was conducted pre-treatment and every 21 d during treatments. Placentas were split into ipsilateral and contralateral sides, dissected (cotyledonary vs. intercotyledonary), and dried. Data were analyzed with treatment, treatment initiation date, and calf sex (when P < 0.25) as fixed effects. Uterine blood flow included day and treatment x day (repeated measures). Dam BW was less (P ≤ 0.01) from d 223 of gestation through parturition for NR dams, but calf BW was not affected (P = 0.72) by treatment. The interaction affected (P < 0.01) heart rate, where NR dams had decreased heart rate after treatments began. Treatment did not affect (P ≥ 0.20) uterine artery blood flow or hemodynamics, but all variables were affected (P ≤ 0.04) by day. Contralateral total and cotyledonary weights tended (P ≤ 0.09) to be greater and ipsilateral and total cotyledonary:intercotyledonary ratios were greater (P ≤ 0.01) for CON. Cotyledon number, cotyledon size, and total cotyledonary, intercotyledonary, and placental weight were not affected (P ≥ 0.15) by treatment. Relative to dam BW, uterine blood flow was not affected (P = 0.83), but relative placental weight tended to be greater (P = 0.09) in NR dams. In the current study, NR dams lost maternal BW during late gestation and had less contralateral placental growth, yet uterine blood flow was maintained and placental size relative to BW ensured fetal growth similar to CON offspring.

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Prostaglandin E2 inhibition of fetal breathing movements is not sustained during prolonged reduced uterine blood flow in sheep

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y98-109 ◽

1998 ◽

Vol 76 (9) ◽

pp. 858-866 ◽

Cited By ~ 1

Author(s):

Carole S Watson ◽

Jacobus H Homan ◽

Susan E White ◽

John R Challis ◽

Alan D Bocking

Keyword(s):

Blood Flow ◽

Ethanol Exposure ◽

Late Gestation ◽

Prostaglandin E ◽

Uterine Blood Flow ◽

Fetal Plasma ◽

Fetal Breathing ◽

Fetal Breathing Movements ◽

Baseline Incidence ◽

And Control

Fetal breathing movements (FBM) are inhibited by both exogenous prostaglandin E2 (PGE2) and ethanol in sheep. Maternal ethanol exposure in late-gestation sheep also increases fetal [PGE2]. However, during prolonged reduced uterine blood flow (RUBF) when [PGE2] in fetal plasma is already elevated, FBM are not inhibited by ethanol. These experiments were designed, therefore, to test the hypothesis that the FBM response to PGE2 is also diminished during RUBF. PGE2 (594 ± 19 ng·min-1·kg-1 fetal body weight) was infused for 6 h into the jugular vein of RUBF (PO2 = 14 ± 1 mmHg (1 mmHg = 133.3 Pa); n = 7) and control (PO2 = 22 ± 1 mmHg (p < 0.01); n = 7) ovine fetuses, and the effect on FBM, electrocortical (ECoG), and electroocular activities was determined. The infusion of PGE2 increased plasma [PGE2] from 881 ± 162 to 1189 ± 114 pg·mL-1 in RUBF fetuses and from 334 ± 72 to 616 ± 118 pg·mL-1 (p < 0.05) in control fetuses. FBM were initially inhibited by PGE2 from 22.5 ± 9.4 and 17.9 ± 6.5% of the time to 6.9 ± 2.4 and 0.5 ± 0.4% (p < 0.01) in RUBF and control fetuses, respectively. FBM remained inhibited in control fetuses throughout the infusion but returned to baseline incidence in RUBF fetuses in the last 2 h of the infusion. These results are consistent with the hypothesis that one component of the adaptative mechanisms of the fetus to prolonged RUBF is an altered response of FBM to exogenous PGE2. We speculate that the lack of a sustained inhibition in FBM during RUBF with infusion of PGE2 may be a result of an alteration in brainstem receptor function or number or local PGE2 removal.Key words: fetal breathing movements, prostaglandin E2, hypoxia, reduced uterine blood flow, ethanol, fetal behaviour.

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Effect of glucose supply on ovine uteroplacental glucose metabolism

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1999.277.4.r947 ◽

1999 ◽

Vol 277 (4) ◽

pp. R947-R958 ◽

Cited By ~ 8

Author(s):

Peter W. Aldoretta ◽

William W. Hay

Keyword(s):

Oxygen Consumption ◽

Glucose Metabolism ◽

Glucose Oxidation ◽

Lactate Production ◽

Glucose Consumption ◽

Reciprocal Relationship ◽

Late Gestation ◽

Fick Principle ◽

Pregnant Sheep ◽

Glucose Supply

To test the hypothesis that glucose supply to the uteroplacenta (UP) regulates UP glucose metabolism into oxidative and nonoxidative pathways, we studied eight late-gestation pregnant sheep at low (LG) and high (HG) maternal glucose concentrations (GM), using Fick principle and tracer glucose methodology. UP glucose consumption (UPGC) correlated directly with GM( r = 0.75, P = 0.0006), and UP glucose decarboxylation ( r = 0.80, P = 0.0001), and lactate production ( r = 0.90, P = 0.0001) rates were directly correlated with UPGC. The combined fractional production rate for lactate, fructose, and CO2 from UPGC was the same in LG and HG periods. The fraction of UP oxygen consumption used for glucose oxidation increased by about 50% from LG to HG conditions; however, there was no change in UP oxygen consumption. Nearly half of UPGC was not accounted for by lactate, fructose, and CO2 production, and about two-thirds of UP oxygen consumption was not accounted for by immediate oxidation of glucose carbon just taken up by the UP. These results indicate that glucose supply directly regulates UP glucose oxidative metabolism and that there is a reciprocal relationship between UP glucose oxidation and the oxidation of other substrates.

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Effects of Fasting on Uterine Blood Flow and Substrate Uptake in Sheep

Journal of Nutrition ◽

10.1093/jn/110.12.2433 ◽

1980 ◽

Vol 110 (12) ◽

pp. 2433-2443 ◽

Cited By ~ 33

Author(s):

Frank H. Morriss ◽

Charles R. Rosenfeld ◽

Sharon S. Crandell ◽

Eugene W. Adcock

Keyword(s):

Blood Flow ◽

Substrate Uptake ◽

Uterine Blood Flow

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Metabolism of the gravid uterus, foetus and utero-placenta at several stages of gestation in cows

The Journal of Agricultural Science ◽

10.1017/s0021859600063309 ◽

1986 ◽

Vol 106 (3) ◽

pp. 437-444 ◽

Cited By ~ 37

Author(s):

L. P. Reynolds ◽

C. L. Ferrell ◽

Debra A. Robertson ◽

S. P. Ford

Keyword(s):

Blood Flow ◽

Deuterium Oxide ◽

N Uptake ◽

Gravid Uterus ◽

Uterine Blood Flow ◽

Indwelling Catheters ◽

Blood Flows ◽

Umbilical Blood ◽

Rate Of Increase ◽

Umbilical Blood Flow

SummaryTo quantify changes in rates of metabolism and nutrient uptake of gravid uteiine, foetal and utero-placental tissues throughout gestation, mature Hereford cows received surgery at 132 ± 0·6 (n = 12), 176 ± 0·5 (n = 8), 220 ±0·4 (n = 11) and 245 ±1·5 (n = 7) days after mating. Indwelling catheters were implanted into a uterine artery and vein of all cows. Foetal catheters also were implanted into an umbilical vein and foetal femoral artery and vein (days 176 and 220) or into a placental artery and two placental veins (days 132 and 245). Approximately 5 days after surgery, deuterium oxide was infused into a foetal femoral venous or placental venous catheter during a 3 h period to quantify uterine and umbilical blood flows by steady-state diffusion methods. Oxygen, glucose, lactate and α-amino acid nitrogen concentrations were determined for uterine and foetal blood samples collected during this procedure.Uterine blood flow increased 4·5-fold (2·92–13·181/min) and umbilical blood flow increased 21-fold (0·28–5·861–min) during the interval of gestation studied. The relative rate of increase of umbilical blood flow was about twice as great as that of uterine blood flow. Uterine arterial and umbilical venous concentrations as well as uterine arterial-venous and umbilical venous-arterial concentration differences in metabolites changed little with stage of gestation. However, because rates of blood flow increased, uptakes of O2, glucose and α-amino N by the gravid uterus and foetus increased as gestation advanced. The proportion of gravid uterine uptakes utilized by the foetus increased from day 137 to 226 for O2 (24–58%) and from day 137 to 180 for glucose (4–19%), then remained relatively constant. The proportion of gravid uterine α-amino N uptake utilized by the foetus remained relatively constant and averaged 60%. A net secretion of lactate from the utero-placenta to the uterine and foetal circulations was observed and increased as gestation advanced. These data indicate that increased rates of uptake or secretion of metabolites by tissues of the gravid uterus can be explained primarily by increased rates of uterine and umbilical blood flows.

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