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Effects of exogenous big endothelin-1 on regional blood flow in fetal lambs
Keiya Fujimori1, Shinya Honda, Minoru Sanpei
1Department of Obstetrics and Gynecology, School of Medicine, Fukushima Medical University, Fukushima, Japan. fujimori@fmu.ac.jp
Objective:
Endothelin-1, a 21 amino acid polypeptide produced by vascular endothelial cells, has potent vasoactive properties. The purpose of this study was to estimate the effects of exogenous big endothelin-1 on fetal lamb circulation.
Methods:
Regional blood flow was measured by the colored microsphere technique during continuous infusion (60 minutes) of big endothelin-1, or saline (control), in 12 chronically instrumented sheep fetuses.
Results:
After 60 minutes of big endothelin-1 administration, the fetal plasma endothelin-1 concentration increased significantly from 24.0 +/- 6.7 to 49.7 +/- 31.4 pg/mL (P = .018) without significant changes in fetal arterial blood gases. Continuous infusion of big endothelin-1 decreased blood flow in most organs except the brain and the heart. After the big endothelin-1 infusion, the blood flow to the brain significantly increased from 158 +/- 51 to 174 +/- 71 mL/min/100 g (P = .002); the blood flow to the heart also increased significantly from 171 +/- 95 to 200 +/- 112 mL/min/100 g (P = .001), respectively.
Conclusion:
Continuous infusion of endothelin-1 decreases blood flow in most of organs except the brain and the heart. It is likely that endothelin-1 plays an important role in fetal redistribution of blood flow.
