Benassayag C, Souski I, Mignot T M, Robert B, Hassid J, Duc-Goiran P, Mondon F, Rebourcet R, Dehennin L, Nunez E A, Ferré F
INSERM U.361, Maternité Port-Royal Cochin, Université René Descartes, 75014 Paris, France.
Biol Reprod. 2001 Mar;64(3):812-21. doi: 10.1095/biolreprod64.3.812.
The status of the corticosteroid-binding globulin (CBG) at the fetomaternal interface, especially in the maternal intervillous blood space (I), was investigated and compared to that of CBG in the maternal (M) and fetal (umbilical arteries [A] and vein [V]) peripheral circulations at term. Immunoquantitation of plasma CBG showed that the CBG concentration in I was 30% less than that in M (P < 0.001) and threefold higher than that in umbilical cord blood (P < 0.001). The microheterogeneity of CBG studied by immunoaffinoelectrophoresis in the presence of concanavalin A and Western blotting indicated that the CBG in I was mainly of maternal origin and different from fetal CBG. A CBG mRNA, but no classic 50- to 59-kDa CBG, was found in isolated term trophoblastic cells. The steroid environment of the CBG in I differed greatly from that in the peripheral maternal and fetal circulations, because the progesterone:cortisol molar ratio in I was 75-fold higher than that in M and 7- to 10-fold higher than that in the fetal circulation. Binding studies revealed that the affinity constants of CBG for cortisol in I, A, and V were significantly lower than that in M plasma (P < 0.02) in their respective hormonal contexts. The binding parameters for I-CBG stripped of endogenous steroids and lipids were close to those for M-CBG but different from those of fetal CBG (P < 0.001). These data reflect the physiological relevance of the CBG-steroid interaction, especially with very CBG-loaded progesterone at the fetomaternal interface during late pregnancy.
研究了皮质类固醇结合球蛋白（CBG）在母胎界面的状态，尤其是在母体绒毛间隙血腔（I）中的状态，并将其与足月时母体（M）和胎儿（脐动脉[A]和脐静脉[V]）外周循环中CBG的状态进行了比较。血浆CBG的免疫定量分析表明，I中CBG的浓度比M中低30%（P<0.001），比脐带血中高3倍（P<0.001）。通过在伴刀豆球蛋白A存在下的免疫亲和电泳和蛋白质印迹法研究CBG的微异质性表明，I中的CBG主要来源于母体，与胎儿CBG不同。在分离的足月滋养层细胞中发现了CBG mRNA，但未发现经典的50至59 kDa的CBG。I中CBG的类固醇环境与母体和胎儿外周循环中的类固醇环境有很大差异，因为I中孕酮与皮质醇的摩尔比比M中高75倍，比胎儿循环中高7至10倍。结合研究表明，在各自的激素环境中，I、A和V中CBG对皮质醇的亲和常数明显低于M血浆中的亲和常数（P<0.02）。去除内源性类固醇和脂质的I-CBG的结合参数接近M-CBG的结合参数，但与胎儿CBG的结合参数不同（P<0.001）。这些数据反映了CBG-类固醇相互作用的生理相关性，尤其是在妊娠晚期母胎界面处与大量CBG结合的孕酮的相互作用。
