Plasma endothelin-1 levels during asphyxia in the fetal goat

The changes in fetal carotid arterial plasma levels of endothelin-1, catecholamines, PO2, PCO2 and pH were measured after intermittent repetitive umbilical cord occlusion in late gestation pregnant goats (n = 9). Endothelin-1 levels increased to 3.58 +/- 0.28 pg/ml immediately after the onset of fetal hypoxia, a level significantly higher than the respective values in the control period (p < 0.05). The elevation of fetal plasma endothelin-1 levels correlated inversely with carotid arterial PO2 (r = -0.41, p < 0.05) and pH (r = - 0.43, p < 0.05). The results suggest that increased endothelin-1 levels may contribute to the maintenance of the fetal circulation during fetal asphyxia.