HYDROPS-FETALIS IN NEPHRECTOMIZED FETAL LAMBS INFUSED WITH ANGIOTENSIN-I

Nine bilaterally nephrectomized fetal sheep were infused for 6 days wi th angiotensin I in sterile water, and five nephrectomized fetal sheep were infused for 6 days with water alone. Total dose of angiotensin w as 13.8 +/- 8.6 (SD) mg/kg fetal dry wt, and the total volumes of infu sed water were 303 +/- 201 and 423 +/- 164 ml, respectively. Of the fe tuses infused with angiotensin I, one was of normal appearance, two sh owed moderate hydrops fetalis, and the remaining fetuses were grossly hydropic. All water-infused fetuses were normal. Their wet-to-dry weig ht ratios were 7.98 and 6.36 (P < 0.015), representing a 25% of normal body weight excess of water in the angiotensin I-infused fetuses. Six days of angiotensin I infusion caused a gradual rise in fetal arteria l blood pressure from 37 +/- 15 to 81 +/- 15 mmHg (P < 0.05) and a gra dual rise in venous blood pressure from 2.7 +/- 1.0 to 10.5 +/- 1.7 mm Hg (P < 0.05). It was concluded that the fetal edema was due to the el evation in venous pressure. Plasma concentrations of Na+, K+, Cl-, HCO 3- total alpha-amino acids, fructose, glucose, and lactate in the fetu s and the ewe did not identify an osmotically active solute responsibl e for the transplacental attraction of excess water into the conceptus , and the mechanism that attracted this excess water across the placen ta remains unclear.