AJP - Regulatory, Integrative and Comparative Physiology, Vol 267, Issue 6 1522-R1527, Copyright © 1994 by American Physiological Society
Hydrops fetalis in nephrectomized fetal lambs infused with angiotensin I
J. J. Faber and D. F. Anderson
Department of Physiology, School of Medicine, Oregon Health Sciences University, Portland 97201.
Nine bilaterally nephrectomized fetal sheep were infused for 6 days with
angiotensin I in sterile water, and five nephrectomized fetal sheep were
infused for 6 days with water alone. Total dose of angiotensin was 13.8 +/-
8.6 (SD) mg/kg fetal dry wt, and the total volumes of infused water were
303 +/- 201 and 423 +/- 164 ml, respectively. Of the fetuses infused with
angiotensin I, one was of normal appearance, two showed moderate hydrops
fetalis, and the remaining fetuses were grossly hydropic. All water-infused
fetuses were normal. Their wet-to-dry weight 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 arterial blood pressure from 37 +/- 15 to 81
+/- 15 mmHg (P < 0.05) and a gradual rise in venous blood pressure from
2.7 +/- 1.0 to 10.5 +/- 1.7 mmHg (P < 0.05). It was concluded that the
fetal edema was due to the elevation in venous pressure. Plasma
concentrations of Na+, K+, Cl-, HCO3-, total alpha-amino acids, fructose,
glucose, and lactate in the fetus and the ewe did not identify an
osmotically active solute responsible for the transplacental attraction of
excess water into the conceptus, and the mechanism that attracted this
excess water across the placenta remains unclear.
