Effects of exogenous big endothelin-1 on regional blood flow in fetal lambs.
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.


CONCLUSIONS
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.
Fujimori
Keiya
K
Department of Obstetrics and Gynecology, School of Medicine, Fukushima Medical University, Fukushima, Japan. fujimori@fmu.ac.jp
Honda
Shinya
S
Sanpei
Minoru
M
Sato
Akira
A
D000818:Animals; D001775:Blood Circulation / Q000187:drug effects*; D001784:Blood Gas Analysis; D001794:Blood Pressure; D019332:Endothelin-1 / Q000097:blood / Q000494:pharmacology*; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D005333:Fetus / Q000187:drug effects*; D006340:Heart Rate, Fetal; D011247:Pregnancy; D012756:Sheep
D019332:Endothelin-1