Jensen Ellen, Wood Charles, Keller-Wood Maureen
Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida 32610, USA.
J Soc Gynecol Investig. 2002 Nov-Dec;9(6):362-71.
This study was designed to test the hypothesis that the increase in maternal cortisol and aldosterone in pregnancy is critical to maternal and fetal homeostasis.
Pregnant ewes were adrenalectomized (at approximately 112 days), and aldosterone and cortisol were given to either normal pregnant level (1 mg/kg per day cortisol and 3 microg/kg per day aldosterone) or nonpregnant level (half the dose of either cortisol or aldosterone). Blood samples for measurement of fetal and maternal plasma electrolytes, cortisol, and adrenocorticotropic hormone (ACTH) were collected at days 120, 125, and 130; fetal and maternal blood pressure and heart rate and maternal plasma volume were measured at days 120 and 130.
Reduction of maternal cortisol or aldosterone decreased maternal plasma volume at 130 days. In the fetuses in the low cortisol group, cortisol concentrations were lower and ACTH concentrations were higher; however, there was no increase in fetal cortisol with age in the low cortisol or low aldosterone groups. Fetal arterial pressure was decreased in all groups of adrenalectomized ewes at 120 days and decreased in the low cortisol group at 130 days. Fetal arterial pressure was significantly related to maternal plasma volume at 130 days. Fetal arterial oxygen tension at 120 days was decreased in fetuses of low aldosterone ewes and was correlated with plasma volume. Overall fetal arterial oxygen tension correlated with fetal cortisol. Fetal ACTH concentrations correlated positively with fetal cortisol but negatively with fetal blood pressure.
Maternal adrenal secretion maintains the normal increase in maternal plasma volume and fetal cortisol and indirectly supports fetal arterial oxygen tension, blood pressure, and adrenal secretion.
本研究旨在验证以下假设，即孕期母体皮质醇和醛固酮的增加对母体和胎儿的内环境稳定至关重要。
对怀孕母羊进行肾上腺切除术（约在妊娠112天时），并给予醛固酮和皮质醇至正常怀孕水平（每天1毫克/千克皮质醇和每天3微克/千克醛固酮）或非怀孕水平（皮质醇或醛固酮剂量减半）。在妊娠120、125和130天时采集血样，用于测定胎儿和母体血浆电解质、皮质醇及促肾上腺皮质激素（ACTH）；在妊娠120和130天时测量胎儿和母体血压、心率及母体血浆容量。
在130天时，母体皮质醇或醛固酮减少会降低母体血浆容量。在低皮质醇组的胎儿中，皮质醇浓度较低而ACTH浓度较高；然而，在低皮质醇或低醛固酮组中，胎儿皮质醇并未随年龄增加。在妊娠120天时，所有肾上腺切除母羊组的胎儿动脉压均降低，在130天时低皮质醇组的胎儿动脉压也降低。在130天时，胎儿动脉压与母体血浆容量显著相关。在妊娠120天时，低醛固酮母羊胎儿的动脉血氧张力降低，且与血浆容量相关。总体而言，胎儿动脉血氧张力与胎儿皮质醇相关。胎儿ACTH浓度与胎儿皮质醇呈正相关，但与胎儿血压呈负相关。
母体肾上腺分泌维持母体血浆容量及胎儿皮质醇的正常增加，并间接支持胎儿动脉血氧张力、血压及肾上腺分泌。
