Maternal and fetal catecholamine responses to acute hypoxemia in Japanese Saanen goats

Our purposes were to investigate the effects of acute hypoxemia on maternal and fetal physiological and biochemical responses in Japanese Saanen goat and to compare these responses to those obtained in other species in the previous studies. Five pregnant Japanese Saanen goats at about 120 days of gestation were operated to make fetal chronic preparation models. After a minimum of 4 days of postoperation, hypoxemia was induced by having the ewe breathe a hypoxic gas mixture (10% O2, 3% CO2, in N2) for 30 min. Maternal PO2 decreased from 84 to 40 mmHg, and fetal PO2 decreased from 22 to 16 mmHg. Only the fetal pH was significantly decreased by hypoxemia. Maternal heart rate increased with increases in arterial pressures. On the other hand, fetal heart rate showed bradycardia with a transient increase in blood pressure. During hypoxemia, maternal catecholamines minimally increased, while fetal plasma concentrations of epinephrine and norepinephrine were significantly increased. These changes in Japanese Saanen goats were first revealed by the current study and were compatible with the previous reports with sheep and monkeys. These observations suggest that the Japanese Saanen goats may be an adequate animal model for investigation of fetal physiology.