Wood C E, Cheung C Y, Brace R A
Department of Reproductive Medicine, University of California, San Diego, La Jolla 92109.
Am J Physiol. 1987 Dec;253(6 Pt 2):R904-9. doi: 10.1152/ajpregu.1987.253.6.R904.
The purpose of this study was to determine whether physiological amounts of cortisol affect the fetal cardiovascular system. Cortisol (4 micrograms/min) or the vehicle was infused intravenously for 5 h into six chronically catheterized sheep fetuses at 127-143 days gestation (term = 145-150 days). In the cortisol-infused animals, plasma cortisol concentration increased from 2.0 +/- 0.6 (SE) to 8.3 +/- 0.9 ng/ml. There was a concomitant decrease in fetal heart rate of 38 beats/min (P less than 1 X 10(-6)) and an increase in arterial pressure. Estimated blood volume decreased by 6% in the cortisol-infused fetuses compared with the vehicle-infused animals (P less than 1 X 10(-4]. In addition, plasma norepinephrine and epinephrine concentrations decreased to 70% of control at the end of the 5-h cortisol infusion, whereas plasma renin concentration decreased to 34% of control. The simultaneous increase in fetal arterial pressure and decrease in estimated blood volume suggest that fetal vascular resistance increased, whereas vascular compliance and/or nonstressed vascular volume decreased. However, this does not appear to be mediated by increases in circulating vasoconstrictor hormone concentrations or increased sympathetic tone. Thus the present study shows that physiological amounts of cortisol have significant effects on the fetal cardiovascular system but the mechanisms are unknown.
本研究的目的是确定生理剂量的皮质醇是否会影响胎儿心血管系统。在妊娠127 - 143天（足月为145 - 150天）时，将皮质醇（4微克/分钟）或赋形剂静脉输注到6只长期插管的绵羊胎儿体内，持续5小时。在输注皮质醇的动物中，血浆皮质醇浓度从2.0±0.6（标准误）增加到8.3±0.9纳克/毫升。胎儿心率随之下降38次/分钟（P < 1×10⁻⁶），动脉压升高。与输注赋形剂的动物相比，输注皮质醇的胎儿估计血容量减少了6%（P < 1×10⁻⁴）。此外，在5小时皮质醇输注结束时，血浆去甲肾上腺素和肾上腺素浓度降至对照值的70%，而血浆肾素浓度降至对照值的34%。胎儿动脉压升高和估计血容量减少同时出现，表明胎儿血管阻力增加，而血管顺应性和/或非应激血管容量减少。然而，这似乎不是由循环中血管收缩激素浓度增加或交感神经张力增加介导的。因此，本研究表明生理剂量的皮质醇对胎儿心血管系统有显著影响，但其机制尚不清楚。
