Plasma renin activity during acute ventilatory hypoxia in the ewe and fetal lamb.
Plasma renin activity (PRA) was determined during ventilatory hypoxia (n = 6) or normoxia (n = 5) in chronically catheterized ewes and fetuses. Compared to identically studied controls, hypoxemic ewes (PaO2 = 34.2 +/- 3 Torr, p less than 0.01) developed significant tachycardia (103 vs. 125 +/- 6, p less than 0.05) without change in blood pressure. Hypoxemic (PaO2 = 9.1 +/- 0.7 Torr, p less than 0.01) fetuses developed hypertension (39.3 vs 44 +/- 2 mm Hg, p less than 0.05), tachycardia (182 +/- 2 vs. 202 +/- 5, p less than 0.05), and elevated hematocrit (34 +/- 1.5 vs. 38.5 +/- 1.8%, p less than 0.02) during hypoxemia. Fetal plasma renin levels increased from 0.26 +/- 0.05 to 7.6 +/- 2.8 ng/ml/h (p less than 0.06) and to 14.7 +/- 5.6 ng/ml/h (p less than 0.05) after 60 and 120 min of hypoxia, respectively. Fetal PRA returned to baseline after 60 min of recovery. Ewe PRA did not change in either group. From these data, we conclude that differences exist between fetal and adult plasma renin levels during hypoxia. The mechanism of this response remains to be clarified.
D000208:Acute Disease; D000818:Animals; D001158:Arteries; D001784:Blood Gas Analysis; D005260:Female; D005312:Fetal Blood / Q000201:enzymology*; D000860:Hypoxia / Q000097:blood* / Q000196:embryology; D012083:Renin / Q000097:blood*; D012756:Sheep
D012083:Renin