Klak J, Hill M, Parízek A, Havlíková H, Bicíková M, Hampl R, Fait T, Sulcová J, Pouzar V, Kancheva R, Stárka L
Institute of Endocrinology, Prague, CZ 116 94, Czech Republic.
Physiol Res. 2003;52(2):211-21.
The levels of four pregnanolone isomers and their polar conjugates and pregnenolone sulfate were measured in the plasma of 13 and 7 women at delivery with subarachnoidal and epidural analgesia, respectively, and in corresponding samples of umbilical plasma using a simple quadrupole GC/MS system with electron impact ionization (pregnenolone isomers), RIA following HPLC separation (pregnenolone) and specific RIA (pregnanolone sulfate). The concentration of epipregnanolone (3beta-hydroxy-5beta-pregnan-20-one) in both maternal and umbilical plasma was much lower than that of other pregnanolone isomers. The levels of 3beta-hydroxy-pregnanolone isomers were significantly higher in the umbilical plasma than in the maternal, while the differences in 3alpha-hydroxy-isomers were insignificant. The differences in conjugates were insignificant with the exception of allopregnanolone, the levels of which were lower in umbilical plasma. In all the pregnanolone isomers, a significantly lower conjugated/unconjugated steroid ratio was found in the umbilical plasma than in the maternal plasma. In addition, time profiles of the steroids were measured around parturition and in the postpartum period in the maternal serum. Similarly, the levels of polar conjugates of all pregnanolone isomers were followed during parturition. Changes in concentrations of free steroids exhibited a similar pattern, with a fall primarily within the first hour after delivery. The decrease in conjugated steroids was shifted to the interval within the first hour and first day after delivery, and the changes were more pronounced. The time profiles of the conjugated/free steroid ratio exhibited a significant decrease within the first hour and the first day after delivery in all of the isomers investigated. A decrease was also observed in the ratio of 3alpha/3beta-isomers and 5alpha/5beta-isomers around parturition. The possible physiological consequences of the findings are indicated.
分别采用具有电子轰击电离功能的简单四极杆气相色谱/质谱系统（用于孕烯醇酮异构体）、高效液相色谱分离后的放射免疫分析法（用于孕烯醇酮）和特异性放射免疫分析法（用于硫酸孕烷醇酮），测定了13例接受蛛网膜下腔镇痛和7例接受硬膜外镇痛的产妇分娩时血浆以及相应脐血样本中四种孕烷醇酮异构体及其极性共轭物和硫酸孕烯醇酮的水平。母血和脐血中表孕烷醇酮（3β-羟基-5β-孕烷-20-酮）的浓度均远低于其他孕烷醇酮异构体。脐血中3β-羟基孕烷醇酮异构体的水平显著高于母血，而3α-羟基异构体的差异不显著。除别孕烷醇酮外，共轭物的差异不显著，脐血中别孕烷醇酮的水平较低。在所有孕烷醇酮异构体中，脐血中类固醇的共轭/非共轭比率显著低于母血。此外，还测定了产妇血清在分娩前后及产后期间类固醇的时间变化曲线。同样，在分娩过程中监测了所有孕烷醇酮异构体极性共轭物的水平。游离类固醇浓度的变化呈现相似模式，主要在分娩后第一小时内下降。共轭类固醇的下降则转移至分娩后第一小时和第一天内，且变化更为明显。在所有研究的异构体中，共轭/游离类固醇比率的时间变化曲线在分娩后第一小时和第一天内显著下降。在分娩前后还观察到3α/3β-异构体和5α/5β-异构体的比率也有所下降。文中指出了这些发现可能的生理后果。
