title: The effect of hypoxia on neurohypophyseal hormone release in fetal and maternal sheep.
abstract: The effect of hypoxemia on arginine vasopressin (AVP) and oxytocin (OT) release was investigated in the chronically catheterized fetus and ewe. During 30 min of 10% maternal oxygen delivery, mean (+/- SEM) arterial PO2 decreased from 105 +/- 10.6 to 48 +/- 3.5 mm Hg in the ewe and from 21 +/- 1.3 to 12 +/- 0.8 mm Hg in the fetus (each P less than 0.001). Arterial PCO2 decreased from 35 +/- 4.4 to 29 +/- 1.0 mm Hg in the ewe, whereas fetal PCO2 decreased from 43 +/- 2.3 to 35 +/- 3.5 mm Hg (P less than 0.05). Blood pH increased from 7.44 +/- 0.03 to 7.56 +/- 0.04 in the ewe (P less than 0.01) and from 7.36 +/- 0.004 to 7.40 +/- 0.006 in the fetuses (P less than 0.01). Baseline mean AVP levels were identical in ewes and fetuses (0.7 +/- 0.1 microU/ml). After 30 min of hypoxia, plasma AVP levels remained unchanged in the ewes (0.9 +/- 0.1), but increased dramatically in the fetuses (47 +/- 21 microU/ml) (P less than 0.001). There was a highly significant correlation between the duration of hypoxia and log fetal AVP concentrations (r = 0.85). The log fetal plasma AVP also was inversely correlated to the log fetal PO2 values (r = 0.83). Mean baseline fetal and maternal plasma OT levels were 2.6 +/- 0.5 microU/ml and 2.2 +/- 0.5 microU/ml, respectively. After 30 min of hypoxia fetal and maternal OT values were 2.9 +/- 0.8 microU/ml (not significant).
mesh_terms: D000818:Animals; D001127:Arginine Vasopressin / Q000097:blood / Q000378:metabolism*; D002245:Carbon Dioxide / Q000097:blood; D005260:Female; D005311:Fetal Hypoxia / Q000503:physiopathology*; D006863:Hydrogen-Ion Concentration; D006935:Hypercapnia / Q000503:physiopathology; D000860:Hypoxia / Q000503:physiopathology*; D008431:Maternal-Fetal Exchange; D010100:Oxygen / Q000097:blood; D010121:Oxytocin / Q000097:blood / Q000378:metabolism*; D010904:Pituitary Gland, Posterior / Q000378:metabolism*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000503:physiopathology*; D012756:Sheep
chemical_list: D001127:Arginine Vasopressin; D002245:Carbon Dioxide; D010121:Oxytocin; D010100:Oxygen