title: Fetal beta-endorphin levels in response to reductions in uterine blood flow.
abstract: Fetal beta-endorphin release has been associated with fetal hypoxia. The purpose of this study was to assess the degree of uterine blood flow reduction needed to elicit fetal beta-endorphin release in the sheep since there is a large reserve of oxygen supply to the fetus. Uterine blood flow was reduced by 26 +/- 2, 46 +/- 3 and 66 +/- 2%, producing fetal oxygen content concentrations of 5.7 +/- 0.6, 4.4 +/- 0.7 and 2.6 +/- 0.3 ml/dl, respectively. Although fetal oxygen concentrations were significantly decreased in the groups with a reduction in uterine blood flow of 46 and 66%, beta-endorphin was elevated only in the latter group. It is speculated that fetal beta-endorphin is released at a level of hypoxia which leads to a decrease in fetal oxygen consumption. A reduction in uterine blood flow of 66% appears to produce a stressful environment for the fetus as measured by fetal plasma beta-endorphin levels.
mesh_terms: D000818:Animals; D001794:Blood Pressure; D004723:Endorphins / Q000097:blood*; D005260:Female; D005312:Fetal Blood / Q000032:analysis; D005333:Fetus / Q000378:metabolism*; D000860:Hypoxia / Q000097:blood; D011247:Pregnancy; D012039:Regional Blood Flow; D012756:Sheep; D014599:Uterus / Q000098:blood supply*; D001615:beta-Endorphin
chemical_list: D004723:Endorphins; D001615:beta-Endorphin