Blood flows and nutrient uptakes in growth-restricted pregnancies induced by overnourishing adolescent sheep.
To establish physiological mechanisms for fetal growth restriction in pregnant adolescent ewes we studied uterine, fetal, and uteroplacental metabolism in ewes offered a high (n = 12) or moderate (n = 10) dietary intake. High intakes decreased placental (226 vs. 414 g, P < 0.001) and fetal weight (3,323 vs. 4,626 g, P < 0.01). Uterine blood flow was reduced absolutely (-36%) but proportional to conceptus weight; umbilical blood flow was reduced absolutely (-37%) and per fetal weight (-15%). Uterine oxygen uptake was decreased per conceptus weight (-14%); there was no change in fetal weight oxygen consumption. Uteroplacental oxygen consumption and clearance were reduced proportional to weight. Similar changes were measured for glucose fluxes and fetal glucose concentration; fetal insulin concentration was reduced. In this model of fetal growth restriction, therefore, maintenance of fetal weight-specific glucose and oxygen consumption rates are producing relative hypoglycemia and hypoxemia. This indicates that increased fetal glucose clearance and/or insulin sensitivity may be operating as compensatory mechanisms to preserve normal fetal metabolism while fetal growth is sacrificed.
Wallace
Jacqueline M
JM
The Rowett Research Institute, Bucksburn, Aberdeen AB21 9SB, United Kingdom. Jacqueline.Wallace@rri.sari.ac.uk
Bourke
Deirdre A
DA
Aitken
Raymond P
RP
Leitch
Neil
N
Hay
William W
WW
D000367:Age Factors; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight; D005260:Female; D005317:Fetal Growth Retardation / Q000503:physiopathology*; D010101:Oxygen Consumption / Q000502:physiology; D010920:Placenta / Q000098:blood supply; D011247:Pregnancy; D011256:Pregnancy Outcome; D012039:Regional Blood Flow / Q000502:physiology; D014471:Umbilical Veins / Q000502:physiology; D014599:Uterus / Q000098:blood supply*
D001786:Blood Glucose