Plasma endothelin-1 and atrial natriuretic peptide levels during prolonged (24-h) non-acidemic hypoxemia in fetal goats

Abstract

Objective: The purpose of this study was to investigate the effects of prolonged (24-h) non-acidemic hypoxemia on plasma endothelin-1 and atrial natriuretic peptide (ANP) in fetal goats. Methods: During continuous infusion of nitrogen into the maternal trachea, fetal plasma endothelin-1 and ANP levels were measured in nine chronically instrumented goat fetuses at 117-129 days' gestation. Endothelin-1 and ANP were measured by radioimmunoassay. Results: Fetal arterial p O 2 decreased significantly from 23.1 - 1.0 mmHg (control) to 15.2 - 0.9 mmHg during the first 2 h of hypoxemia and to 15.7 - 1.1 mmHg at the end of the experimental period of hypoxemia. The plasma endothelin-1 concentration increased from 10.6 - 1.9 pg/ml to 20.4 - 4.3 pg/ml ( p < 0.05) during the first 2 h and was 19.7 - 2.4 pg/ml ( p < 0.01) at the end of the experimental period. The plasma ANP concentration also increased, from 20.3 - 5.5 pg/ml to 23.0 - 4.7 pg/ml in the first 2 h and then to 58.0 - 8.8 pg/ml ( p < 0.05) at the end of the experimental period. There was a significant negative correlation between fetal plasma endothelin-1 and p O 2, but no significant correlation was found between fetal plasma ANP and p O 2 . Conclusions: Prolonged non-acidemic hypoxemia induces a continuous increase in fetal plasma endothelin-1 and ANP levels. Fetal plasma ANP increases time-dependently but endothelin-1 remains constant during hypoxemia.