Baggia S, Albrecht E D, Babischkin J S, Pepe G J
Department of Physiology, Eastern Virginia Medical School, Norfolk 23501.
Endocrinology. 1990 Oct;127(4):1735-41. doi: 10.1210/endo-127-4-1735.
In baboons, transplacental cortisol (F)/cortisone (E) metabolism changes from reduction (E to F) at midgestation to oxidation (F to E) near term when estrogen becomes elevated. Indeed, estrogen regulates the placental microsomal 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) enzyme catalyzing F oxidation. However, regulation of 11 beta-HSD-reductase (E to F) is unknown, because this enzyme is destroyed by microsomal isolation. Therefore, we used cell culture to determine the role of estrogen on placental reduction of E to F and to ascertain whether estrogen regulation of the oxidation of F to E was specific to trophoblast. Placentas were obtained on day 165 (n = 6; term, day 184) and on day 100 of gestation from baboons untreated (n = 8) or treated (n = 6) with 50-mg implants of androstenedione (delta 4A) inserted sc in the mother between days 70 and 100 of gestation to increase placental estrogen production. After removal of fetal membranes, the decidua basalis and trophoblast were separated, rinsed repeatedly in medium-199, minced, and then incubated in trypsin/DNase. Dispersed cells were layered onto a discontinuous Percoll gradient (5-70%), and purified cytotrophoblast (TC; 1.048-1.062 g/ml) and decidua (DC; 1.048-1.062 g/ml) were harvested. After incubation in media containing 10% fetal bovine serum to permit attachment, cells were incubated (24 h) in Dulbecco's modified Eagle's medium containing 10,100, or 500 ng [3H]F or [3H]E. F and E in medium were purified by HPLC and the interconversion of F/E calculated. Equilibrium was achieved by 12 h, and F/E metabolism was proportional to cell number and substrate (10-500 ng) concentration. At substrate concentrations of 500 ng/ml, the reduction of E to F (range, 81-195 ng F produced/24 h) in the DC (0.5 x 10(6) cells) was greater (P less than 0.05) than oxidation of F to E (19-28 ng E/24 h) in all groups. This pattern of metabolism by DC was not affected by time of gestation or treatment with delta 4A. In the TC (2.5 x 10(6) cells), oxidation of F to E always exceeded (P less than 0.05) reduction of E to F. Moreover, the conversion of F to E by TC of day 100 (86 +/- 26 ng E/24 h; mean +/- SE) was increased (P less than 0.05) by delta 4A (195 +/- 35) and greater (P less than 0.05) at day 165 (213 +/- 40). In contrast, TC metabolism of E (21-57 ng F/24 h) was similar in all groups.(ABSTRACT TRUNCATED AT 400 WORDS)
在狒狒中，经胎盘的皮质醇（F）/可的松（E）代谢在妊娠中期由还原（E转化为F）转变为在妊娠晚期雌激素升高时的氧化（F转化为E）。实际上，雌激素调节催化F氧化的胎盘微粒体11β-羟基类固醇脱氢酶（11β-HSD）。然而，11β-HSD还原酶（E转化为F）的调节尚不清楚，因为这种酶在微粒体分离过程中会被破坏。因此，我们采用细胞培养来确定雌激素在胎盘将E还原为F过程中的作用，并确定雌激素对F氧化为E的调节是否对滋养层具有特异性。在妊娠165天（n = 6；足月为184天）和妊娠100天时，从未经处理（n = 8）或经处理（n = 6）的狒狒获取胎盘，处理组在妊娠70至100天期间，经皮下植入50毫克雄烯二酮（δ4A）以增加胎盘雌激素的产生。去除胎膜后，将基蜕膜和滋养层分离，在199培养基中反复冲洗并切碎，然后在胰蛋白酶/脱氧核糖核酸酶中孵育。将分散的细胞铺在不连续的 Percoll 梯度（5 - 70%）上，收获纯化的细胞滋养层（TC；1.048 - 1.062克/毫升）和蜕膜（DC；1.048 - 1.062克/毫升）。在含有10%胎牛血清的培养基中孵育以使其贴壁后，将细胞在含有10、100或500纳克[3H]F或[3H]E的 Dulbecco改良Eagle培养基中孵育（24小时）。通过高效液相色谱法纯化培养基中的F和E，并计算F/E的相互转化。12小时达到平衡，F/E代谢与细胞数量和底物（10 - 50纳克）浓度成正比。在底物浓度为500纳克/毫升时，DC组（0.5×10⁶个细胞）中E还原为F（范围为81 - 195纳克F产生/24小时）比所有组中F氧化为E（19 - 28纳克E/24小时）更显著（P < 0.05）。DC组的这种代谢模式不受妊娠时间或δ4A处理的影响。在TC组（2.5×10⁶个细胞）中，F氧化为E总是超过（P < 0.05）E还原为F。此外，100天的TC组中F转化为E（86 ± 26纳克E/24小时；平均值 ± 标准误）因δ4A处理而增加（P < 0.05）至（195 ± 35），且在165天时更大（P < 与所有组中F氧化为E（19 - 28纳克E/24小时）相比，DC组中E还原为F（范围为81 - 195纳克F产生/24小时）更显著（P < 0.05）。DC组的这种代谢模式不受妊娠时间或δ4A处理的影响。在TC组（2.5×10⁶个细胞）中，F氧化为E总是超过（P < 0.05）E还原为F。此外，100天的TC组中F转化为E（86 ± 26纳克E/24小时；平均值 ± 标准误）因δ4A处理而增加（P < 0.05）至（195 ± 35），且在165天时更大（P < 0.05）（213 ± 40）。相比之下，所有组中TC对E的代谢（21 - 57纳克F/24小时）相似。（摘要截短至400字） 0.05）（213 ± 40）。相比之下，所有组中TC对E的代谢（21 - 57纳克F/24小时）相似。（摘要截短至400字）
