Blunted response of maternal ovine placental lactogen levels to arginine stimulation after single umbilical artery ligation in pregnant sheep.
Ovine placental lactogen levels in the maternal circulation are significantly reduced after single umbilical artery ligation in pregnant sheep. We report the ovine placental lactogen response to high-dose amino acid stimulation in four ewes with fetuses that underwent single umbilical artery ligation and six control ewes with fetuses that underwent sham operation. After maternal infusion with 50 gm of arginine in 350 ml of distilled water, mean ovine placental lactogen levels in ewes with fetuses that underwent single umbilical artery ligation increased by 170%, while mean levels in control ewes increased by 294%. Maternal infusions with hypertonic saline solution of osmolality and volume equal to those of the arginine solutions failed to increase maternal ovine placental lactogen levels. Fetal well-being, both during and after the maternal arginine infusions, was confirmed by unchanged fetal arterial blood gases and catecholamines. The ovine placental lactogen levels in the fetal circulation were not altered by maternal arginine infusion. These data suggest that the correlation between maternal ovine placental lactogen levels and functioning placental mass may be enhanced by arginine stimulation. The possible use of this provocation of placental lactogen levels as a test of placental function in clinical practice is discussed.
D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D005260:Female; D005312:Fetal Blood / Q000032:analysis; D005333:Fetus / Q000378:metabolism; D008026:Ligation; D010920:Placenta / Q000187:drug effects / Q000378:metabolism; D010922:Placenta Diseases / Q000378:metabolism*; D010927:Placental Insufficiency / Q000378:metabolism*; D010928:Placental Lactogen / Q000378:metabolism*; D011247:Pregnancy; D011817:Rabbits; D014469:Umbilical Arteries / Q000601:surgery
D001127:Arginine Vasopressin; D010928:Placental Lactogen