Placental hormones and fetal-placental development
Placental hormones and fetal-placental development
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DOI：
10.1016/j.anireprosci.2004.04.008
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发表时间：
2004-07-01
影响因子：
2.2
通讯作者：
Gootwine, E
中科院分区：
文献类型：
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作者：
Gootwine, E
在各种情况下，胎盘对生长促进物质的产生的调节与母体器官对类似化合物产生的调节方式不同。基因复制是促进胎盘特异性内分泌活动进化的机制之一。牛、绵羊和山羊虽然在进化上相关，但在胎盘生长激素（GH）和催乳素（PRL）样激素的进化方式上彼此显着不同。牛只携带一个GH基因拷贝，目前还没有证据表明胎盘中有该单个GH基因拷贝的表达。另一方面，绵羊GH基因已被复制，并且两个oGH拷贝在妊娠早期在胎盘中表达。催乳素基因在反刍动物中的重复导致形成特定的胎盘表达的催乳素相关基因，包括胎盘催乳素（PL）基因。在同源状态下，羊PL表现PRL活性，但拮抗GH活性。绵羊PL活性可由PRL受体或GH和PRL受体的异源二聚体介导，为生长激素活性提供了一种新的调节机制，该机制依赖于GH和PRL受体在同一细胞中的共存。胎盘内分泌活动的另一个机制是通过遗传印记沉默等位基因。胎盘基因遗传印记的破坏被认为是体细胞核移植产生的克隆胎儿丢失的原因之一。(C)2004 Elsevier B.V.保留所有权利。
Production of growth promoting substances by the placenta is regulated differently from the way production of similar compounds is regulated by maternal organs in various cases. Gene duplication is one of the mechanisms that facilitated the evolution of placental specific endocrine activity. Cattle, sheep and goats, although evolutionarily related, differ significantly from each other in the way their placental growth hormone (GH) and prolactin (PRL)-like hormones have evolved. Cattle carry one copy of the GH gene and there is no evidence yet for expression of that single GH gene copy in the placenta. On the other hand, the ovine GH gene has been duplicated and both oGH copies are expressed in the placenta during early stages of gestation. Prolactin gene duplication in ruminants resulted in the formation of specific placental-expressed prolactin-related genes including the placental lactogen (PL) gene. In homologous state, ovine PL manifests PRL activity, but antagonizes GH activity. Ovine PL activity which can be mediated by PRL receptors or by hetero-dimerization of GH and PRL receptors, provide a novel regulatory mechanism for somatogenic activity dependent on the coexistence of both GH and PRL receptors in the same cells. Another mechanism for specific placental endocrine activity is silencing of the alleles through genetic imprinting. Disruption of genetic imprinting of placental genes has been proposed as one of the explanations for the loss of cloned fetuses generated by somatic cell nuclear transfer. (C) 2004 Elsevier B.V. All rights reserved.