Lewis R M, Batchelor D C, Cockrem J F, Johnston B M, Bassett N S, Skinner S J
Research Centre for Developmental Medicine and Biology, University of Auckland, New Zealand.
Reprod Fertil Dev. 1998;10(4):341-6. doi: 10.1071/r98031.
Fetal exposure to high concentrations of corticosteroids in the rat is associated with elevated blood pressure in postnatal life. In this study we have investigated indicators of corticosteroid activity in fetal spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) in order to determine whether fetal corticosteroid exposure is increased in the SHR. Placental 11beta-hydroxysteroid dehydrogenase (11beta-HSD) activity, which prevents maternal steroids from crossing the placenta, was not impaired in the SHR. Concentrations of amniotic fluid corticosterone were significantly decreased in the SHR compared with the WKY at fetal Day 20, but were not significantly different on fetal Days 16 or 22. This suggests that rather than increased exposure to corticosteroids in the SHR fetus corticosteroid exposure may be reduced. Expression of lung surfactant protein A (Sp-A), a gene induced in late gestation by corticosteroids, was decreased in the SHR. In addition, differences in amniotic fluid electrolyte concentrations were observed which may reflect delayed renal maturation in the fetal SHR. These data suggest that the SHR fetus is exposed to low concentrations of corticosteroids and that the late gestation rise in fetal corticosteroid may be delayed in the SHR.
在大鼠中，胎儿暴露于高浓度皮质类固醇与出生后血压升高有关。在本研究中，我们调查了胎儿自发性高血压大鼠（SHR）和Wistar-Kyoto大鼠（WKY）中皮质类固醇活性指标，以确定SHR中胎儿皮质类固醇暴露是否增加。胎盘11β-羟基类固醇脱氢酶（11β-HSD）活性可阻止母体类固醇穿过胎盘，在SHR中并未受损。在胎儿第20天时，与WKY相比，SHR羊水中皮质酮浓度显著降低，但在胎儿第16天或22天时无显著差异。这表明，SHR胎儿的皮质类固醇暴露可能减少，而非增加。肺表面活性物质蛋白A（Sp-A）的表达在SHR中降低，该基因在妊娠后期由皮质类固醇诱导。此外，观察到羊水电解质浓度存在差异，这可能反映了胎儿SHR肾脏成熟延迟。这些数据表明，SHR胎儿暴露于低浓度皮质类固醇，且胎儿皮质类固醇在妊娠后期的升高在SHR中可能延迟。
