MATERNAL-FETAL STEROID REGULATION

母胎类固醇调节

• 批准号: 2196995
• 负责人: Eugene D. Albrecht
• 金额: $ 46.88万
• 依托单位: UNIVERSITY OF MARYLAND BALTIMORE
• 依托单位国家: 美国
• 财政年份: 1980
• 资助国家: 美国
• 起止时间: 1980-07-01 至 1997-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2196995
• 关键词: adrenocorticotropic hormone; baboons; birth; cytochrome P450; embryo /fetus; enzyme activity; estrogens; gestational age; hormone receptor; hormone regulation /control mechanism; hypothalamic pituitary axis; in situ hybridization; low density lipoprotein; messenger RNA; northern blottings; placenta; pregnancy; progesterone; radioimmunoassay; radiotracer; statistics /biometry; steroid hormone biosynthesis; steroid hormone metabolism

In human and nonhuman primate pregnancy, progesterone (P4) and estrogen synthesized within the placenta and cortisol (F) produced by the fetal adrenal late in gestation play major roles in pregnancy maintenance and maturation of the fetus. The applicants have shown that estrogen plays a central integrative role in regulating placental P4 synthesis and in initiating de novo F synthesis by the fetal adrenal near term by modulating trans-placental F and cortisone (E) metabolism, which we propose activates the fetal hypothalamic-hypophyseal-adrenocortical axis (HPAA). The proposed consortium study will employ in vivo experimental paradigms in pregnant baboons and molecular biological methodologies to test the hypotheses that: [1] a developmental regulation of P4 biosynthesis exists which involves enhanced expression/translation of the mRNAs for the low density lipoproteins (LDL) receptor and mitochondrial cytochrome P450 cholesterol side-chain cleavage (scc) enzyme system within the placenta by estrogen; [2] the ontogenesis of fetal adrenal F production elicited by estrogen-induced alterations in transplacental F and E metabolism results from activation of corticotrophin releasing hormone (CRH)-ACTH production by the fetal hypothalamus-pituitary; and [3] that the increase in activities of the enzymes 17alpha-hydroxylase/17-20 lyase (17alpha-OHase) and delta5-3beta-hydroxysteroid dehydrogenase (3beta-HSD) catalyzing de novo F production by the fetal adrenal near term, which result from activation of the HPAA by estrogen-induced changes in placental F-E metabolism, is the result of enhanced expression/translation of the mRNAs for these enzymes by fetal pituitary ACTH. In Study I, placental mRNAs and levels of LDL receptor and P450scc/adrenodoxin will be quantified by Northern/slot hybridization and Western immunoblot analyses, respectively, in baboons of early, mid and late gestation when estrogen is normally increasing, late in gestation following suppression of estrogen production by fetal hypophysectomy to remove ACTH-dependent C19-steroid precursors, and at midgestation in animals in which estrogen has been elevated by maternal administration of estradiol. In Experiment II-1, pituitary ACTH production will be determined by in vitro perifusion and expression of CRH and POMC mRNAs measured by quantitative in situ hybridization of hypothalamic/pituitary tissue obtained from baboon fetuses in which estrogen has been elevated and de novo F production initiated prematurely at midgestation and confirmed by analysis of adrenal steroidogenesis by in vitro perifusion. The importance of fetal ACTH per se to the initiation of de novo F production will be determined by treating baboon fetuses in utero with ACTH at midgestation. In Experiment II-2, the mRNAs (Northern/slot blot) for and peptide levels (Western immunoblot) of 3beta-HSD and 17alpha- OHase will be quantified in fetal adrenals obtained at midgestation following administration of estrogen or treatment of the fetus with ACTH and at term following fetal hypophysectomy with/without supplementation with ACTH. Results from these studies are expected to provide new insight into the regulation, at the genomic level, of fetoplacental steroid hormone biosynthesis, and thus ultimately improve our knowledge of the regulation of pregnancy maintenance and development of fetal self-sufficiency.

在人类和非人类的灵长类动物妊娠中，孕激素（P4）和雌激素 在胎儿产生的胎盘和皮质醇（F）中合成 妊娠后期肾上腺在妊娠维持中起主要作用 胎儿的成熟。 申请人表明雌激素在 中心综合在调节胎盘P4合成和 通过调节，胎儿肾上腺启动从头合成 跨置换型F和可的松（E）代谢，我们提出激活 胎儿下丘脑 - 摩托医生 - 肾上腺皮质轴（HPAA）。 这 拟议的财团研究将在体内实验范例中 怀孕的狒狒和分子生物学方法论 假设：[1]存在P4生物合成的发展调节 这涉及低点mRNA的表达/翻译 密度脂蛋白（LDL）受体和线粒体细胞色素P450 胆固醇侧链裂解（SCC）酶系统在胎盘中通过 雌激素[2]胎儿肾上腺F产生的个体发生由 雌激素诱导的移植F和E代谢结果改变 从激活皮质营养素释放激素（CRH） - ACTH产生 由胎儿下丘脑垂体； [3]增加 酶的活性17Alpha-羟化酶/17-20裂解酶（17Alpha-Ohase） 和delta5-3beta-羟基固醇脱氢酶（3Beta-HSD）催化DE 胎儿肾上腺近期产生的Novo f生产，这是由 通过雌激素诱导的胎盘F-E的变化激活HPAA 代谢，是mRNA表达/翻译增强的结果 这些酶通过胎儿垂体ACTH。 在研究I中，胎盘mRNA和 LDL受体和P450SCC/肾上腺素毒素的水平将通过 北/插槽杂交和西部免疫印迹分析分析 在雌激素通常是早期，中期和晚期的狒狒中 增加雌激素产生后的妊娠后期 通过胎儿下生理切除术以去除依赖ACTH的C19类固醇前体， 在动物的中期，雌激素已经升高 雌二醇的产妇给药。 在实验II-1中，垂体ACTH 生产将由CRH的体外促进和表达确定 和POMC mRNA通过定量的原位杂交测量 从狒狒胎儿获得的下丘脑/垂体组织 雌激素已经升高，从头产生过早地产生 中期，通过分析肾上腺类固醇生成的证实 体外促进。 胎儿ACTH本身对开始的重要性 从头生产将通过在子宫内治疗狒狒胎儿来确定 与ACTH处于中期。 在实验II-2中，mRNA（北/插槽 3Beta-HSD和17Alpha-的印迹）和肽水平（西部免疫印迹） OHASE将在中间寄生的胎儿肾上腺中进行量化 在给予雌激素或用ACTH治疗胎儿之后 并在胎儿下生理切除术后接受/不补充 与acth。 这些研究的结果有望提供新的见解 在基因组水平的调节中，胎儿类固醇激素 生物合成，因此最终提高了我们对调节的了解 维持妊娠和胎儿自给自足的发展。