Effects of undernutrition and exercise during late pregnancy on uterine, fetal and uteroplacental metabolism in the ewe

Abstract

1. Uterine, umbilical and, by difference, uteroplacental net uptakes of oxygen, glucose, lactate and 3-hydroxybutyrate (uterine uptake only) were measured in single-pregnant ewes which were either well-fed throughout, or severely undernourished for 8-20 d during late pregnancy. All animals were studied while standing at rest and then while walking on a treadmill at 0.7 m/s on a 10" slope for 60 min.2. Undernutrition did not significantly affect fetal or placental weights at 143 d gestation but caused a 14% decrease in maternal live weight. Uterine blood flow was decreased by 32% and was associated with a significant decrease in uteroplacental oxygen uptake; neither umbilical blood flow nor fetal 0, uptake were affected by maternal plane of nutrition. Maternal and fetal hypoglycaemia in underfed ewes was accompanied by 4&63 % decreases in uterine, umbilical and uteroplacental net uptakes of glucose, and similar declines in uterine and umbilical glucose/O, quotients. Moderate maternal hyperketonaemia was associated with 2.5-fold and 3-fold increases in uterine net uptake of 3-hydroxybutyrate and 3-hydroxybutyrate/O2 quotient respectively.3. Exercise caused significant decreases in uterine blood flow in fed and underfed ewes but did not affect uterine or umbilical 0, uptakes; uterine net glucose uptake increased in most ewes but umbilical uptake was not significantly affected. Umbilical net uptake of lactate was significantly reduced. In underfed ewes, the extent of hyperketonaemia was significantly reduced by exercise.4. Contrary to earlier proposals, the ovine pregnant uterus is sensitive and adaptable to long-and short-term alterations in maternal energy balance, as achieved by chronic undernutrition and exercise respectively. Thus, the fetus and placenta significantly add to, but do not necessarily have priority over the energy demands of other tissues of the ewe.

The differential effects of the timing of maternal nutrient restriction in the ovine placenta on glucocorticoid sensitivity, uncoupling protein 2, peroxisome proliferator-activated receptor-γ and cell proliferation

“…During maternal NR in sheep, maternal glucose concentrations are either unchanged (Edwards & McMillen 2001, Bispham et al 2003, Sosa et al 2009 or reduced (Heasman et al 1998a, Osgerby et al 2002, Quigley et al 2008, whereas plasma NEFA concentrations are consistently raised (Chandler et al 1985, Bauer et al 1995, Heasman et al 1998a, Brameld et al 2000, Bispham et al 2003, Quigley et al 2008, Sosa et al 2009). Fetal plasma NEFA concentrations, however, remain unchanged (Bauer et al 1995) as transfer of NEFA across the ovine placenta is limited (Hull et al 1979).…”

“…Fetal plasma NEFA concentrations, however, remain unchanged (Bauer et al 1995) as transfer of NEFA across the ovine placenta is limited (Hull et al 1979). If raised, maternal NEFA were accompanied by reduced utero-placental oxygen uptake (Chandler et al 1985), this could result in increased production of placental reactive oxidation species as a consequence of enhanced lipid oxidation. In the present study, we found upregulation of both PPARG and UCP2 when NR was specifically targeted from day 66 to 110 of gestation.…”

“…Following maternal NR, maternal glucose concentrations can be reduced (Heasman et al 1998a) and plasma non-esterified fatty acids (NEFA) increased (Heasman et al 1998a, Bispham et al 2003. While placental transfer of NEFA to the fetus in sheep is normally limited (Hull et al 1979), when nutrient supply is constrained they may play a role in placental metabolism in conjunction with increased uptake of ketone bodies (Chandler et al 1985). One factor that could regulate oxidative metabolism in the placenta is the mitochondrial UCP2 by promoting NEFA oxidation in preference to carbohydrate (Pecqueur et al 2008).…”

Revue bibliographique : Variations quantitatives et métabolisme des lipides dans les tissus adipeux et le foie au cours du cycle gestation-lactation 2e partie : chez la brebis et la vache

“…Les Lindsay, 1982a). Les corps cétoniques contribueraient en particulier à 15-45 % de la production de C0 2 par les muscles et à 10-20 % de celle de l'utérus gravide, qui consommerait 20-25 % des corps cétoniques produits par la brebis à jeun (Pethick et Lindsay, 1982a ;Chandler et al, 1983Chandler et al, , 1985. Les tion des lipides corporels et les rendements énergétiques (Robinson et al, 1974 ;Cowan et al, 1961 ;Benazzouz et Thériez, 1985 (Malterre, 1986a).…”

Effect of protein or energy restriction during late gestation on hormonal and metabolic status in pregnant goats and postnatal male offspring

“…Considering a higher NEFA concentration would help restrain the use of GLU to synthesize glycogen and fat, the elevated plasma NEFA, similar to lower insulin concentration or higher Cor or TG concentration, observed in the nutritional restricted mothers could be interpreted as an adjustment necessary to meet their energy demands. However, it should be noted that enhanced NEFA concentration He, Sun, Beauchemin, Yang, Tang, Zhou, Han, Wang, Kang and Tan in pregnant mothers would be accompanied by reduced utero-placental oxygen uptake (Chandler et al, 1985), resulting in increased production of placental reactive oxidation species. Consequently, lipid oxidation for uterine placenta was enhanced, which may have a negative impact on fetal development.…”