Effects of nitric oxide and prostacyclin on hemodynamic response by big endothelin-1 in near term fetal sheep.
OBJECTIVE
To measure plasma concentrations of endothelin (ET)-1, NO metabolites (nitrate/nitrite; NOx) and 6-keto PGF1 alpha (PGF1 alpha) in maternal and fetal sheep blood, and to evaluate the effects of big ET-1 on hemodynamic response, blood gases and NO and 6-keto PGF1 alpha production in near term fetal sheep.


METHODS
Hemodynamic parameters were measured during infusion of big ET-1 into the carotid vein in chronically catheterized fetal sheep on day 125 of gestation. Fetal arterial blood samples were obtained for ET-1, PGF1 alpha) and nitrate/nitrite (NOx) measurements.


RESULTS
ET-1, NOx and PGF1 alpha plasma concentrations were all significantly higher in fetal compared with the maternal plasma. Big ET-1 significantly decreased fetal systolic and diastolic blood pressure and significantly increased fetal heart rate. Big ET-1 stimulated plasma PGF1 alpha), but not NOx , concentration.


CONCLUSIONS
Circulatory regulating factors in the fetus were up-regulated. The effects of ET-1 on fetal hemodynamic response may be mediated via prostacyclin, but not via the NO pathway.
Okawa
Toshiaki
T
Department of Obstetrics and Gynecology, Fukushima Medical University School of Medicine, Fukushima 960-1295, Japan. okawat@fmu.ac.jp
Honda
Shinya
S
Sanpei
Minoru
M
Ishida
Tomohiko
T
Fujimori
Keiya
K
Sato
Akira
A
D000818:Animals; D001784:Blood Gas Analysis; D019332:Endothelin-1 / Q000097:blood / Q000494:pharmacology*; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D006439:Hemodynamics / Q000187:drug effects; D009569:Nitric Oxide / Q000097:blood*; D011247:Pregnancy; D011460:Prostaglandins F / Q000097:blood*; D012756:Sheep
D019332:Endothelin-1; D011460:Prostaglandins F; D009569:Nitric Oxide; C100006:prostaglandin F1