Sameshima H, Ikenoue T, Kamitomo M, Sakamoto H
Department of Obstetrics and Gynecology, Miyazaki Medical College, Japan.
J Matern Fetal Med. 1996 Sep-Oct;5(5):262-7. doi: 10.1002/(SICI)1520-6661(199609/10)5:5<262::AID-MFM4>3.0.CO;2-F.
The purpose of the present study was to determine the effect of prolonged hypoxemia without acidemia on fetal stress hormones. Twenty-four-hour hypoxemia was conducted in nine chronically catheterized pregnant goats to determine fetal plasma concentrations of arginine vasopressin (AVP), epinephrine (E), and norepinephrine (NE). Nine experiments were performed. Six resulted in nonacidemic, steady-state hypoxemia, and three incidentally resulted in hypoxemia with progressive acidemia. In steady-state hypoxemia, fetal PO2 decreased significantly from 28.1 +/- 2.4 Torr to 18.8 +/- 2.5 Torr, fetal PCO2 also decreased significantly by about 5 Torr, and pH values did not change significantly. Fetal plasma concentrations of AVP, E, and NE were significantly increased at 1 h of hypoxemia. As hypoxemia continued, AVP returned to control level by 24 h, while E and NE remained elevated throughout the hypoxemic period. In the three experiments with progressive acidemia, AVP, E, and NE increased further as fetal acidosis progressed. We conclude that fetal AVP acts as a shorter-term stress hormone than E and NE in steady-state hypoxemia. This adaptive response is present without progressive acidosis. We also conclude that accompanying acidemia is a more potent stimulus for AVP, E, and NE than isolated hypoxemia during longer-term studies.
本研究的目的是确定无酸血症的长期低氧血症对胎儿应激激素的影响。对9只长期插管的怀孕山羊进行了24小时低氧血症实验，以测定胎儿血浆中精氨酸加压素（AVP）、肾上腺素（E）和去甲肾上腺素（NE）的浓度。共进行了9次实验。其中6次导致非酸血症的稳态低氧血症，3次偶然导致伴有进行性酸血症的低氧血症。在稳态低氧血症中，胎儿的PO2从28.1±2.4 Torr显著降至18.8±2.5 Torr，胎儿的PCO2也显著下降约5 Torr，而pH值无显著变化。低氧血症1小时时，胎儿血浆中AVP、E和NE的浓度显著升高。随着低氧血症的持续，AVP在24小时时恢复到对照水平，而E和NE在整个低氧血症期间一直升高。在3次伴有进行性酸血症的实验中，随着胎儿酸中毒的进展，AVP、E和NE进一步升高。我们得出结论，在稳态低氧血症中，胎儿AVP作为一种应激激素，其作用时间比E和NE短。这种适应性反应在无进行性酸中毒的情况下也存在。我们还得出结论，在长期研究中，伴随的酸血症比单纯的低氧血症对AVP、E和NE是更强有力的刺激因素。
