The Human placenta: an atypical endocrine organ Authors Danièle Evain-Brion Andre Malassiné Abstract The human placenta is characterized by the intensity and the specificity of its endocrine functions. Placental hormones are required for the establishment and maintenance of pregnancy, the adaptation of the maternal organism to pregnancy, fetal growth and well being, and the development of the mechanisms involved in parturition. The endocrine tissue of the placenta is the syncytiotrophoblast, which covers the chorionic villi, the main structure of exchange. Primary cultures of villous cytotrophoblasts have provided insight into the mechanisms involved in syncytiotrophoblast formation by cell-cell fusion. Bathing in maternal blood, the syncytiotrophoblast secretes the majority of its polypeptide hormones into maternal circulation. Among those, hCG (human chorionic gonadotropin) plays an essential role in the maintenance of the corpus luteum and is directly implicated in trophoblastic differentiation. The placental GH (growth hormone) secreted continuously by the syncytiotrophoblast replaces the maternal pituitary GH during pregnancy. Capturing the cholesterol from the maternal lipoproteins, the syncytiotrophoblast synthesizes large amounts of progesterone essential for uterine quiescence. Deprived of cytochrome P450 17αhydroxylase/17-20lyase, it uses the maternal and fetal adrenal androgens to synthesize estrogens. The observation of any maternal hormonal anomaly during pregnancy must take into account these data and, in particular, the enzymatic characteristics of the placenta. Downloads Text complet (Català) Published 2007-12-28 Issue 56, 2005 : Endocrinologia molecular / Jaume Reventós editor Section Articles License The intellectual property of the articles belongs to the respective authors. At the time of submitting the articles to Treballs de la Societat Catalana de Biologia, authors accept the following terms: — Authors assign to the SCB (a subsidiary of the Institut d’Estudis Catalans) the rights of reproduction, public communication (including communication through social networks) and distribution of the articles submitted for publication to Treballs de la Societat Catalana de Biologia, in any form and medium, including digital platforms. The Publications Committee reserves the right to accept or refuse submitted articles and the right to make any editorial changes it deems appropriate. If the suggested changes are accepted by authors, they should re-submit the article with such changes. — Authors answer to the SCB for the authorship and originality of submitted articles. In other words, authors assure that submitted articles do not contain fragments of works by other authors or fragments of their own previously published works; that the content of articles is original, and that the copyright of third parties is not infringed upon. Authors accept this responsibility and undertake to hold harmless the SCB for any loss or damage resulting from non-compliance with this obligation. Furthermore, they should include a statement in articles submitted to the journal regarding their responsibility for the content of the articles. — Authors are responsible for obtaining permission for the reproduction of all graphic material included in articles, and they should moreover ensure that images, videos, etc., have been created with the consent of the individuals appearing in them, and that material belonging to third parties is clearly identified and acknowledged as such within the text. Likewise, authors should provide the respective consents and authorisations to the SCB when submitting articles. — The SCB is exempt from any liability arising from the possible infringement of intellectual property rights by authors. In all cases, it undertakes to publish corrections, clarifications, retractions and apologies, if necessary. — Unless otherwise stated in the text or in the graphic material, the contents published in the journal are subject to an Attribution - NonCommercial - NoDerivs 3.0 Spain (by-nc-nd) license from Creative Commons, the full text of which may be consulted at https://creativecommons.org/licenses/by-nc-nd/3.0/es/deed.en. Therefore, the general public is authorised to reproduce, distribute and communicate articles as long as their authorship and publishing entity are acknowledged, and no commercial use is made of them nor derivative work produced from them. — The journal is not responsible for the ideas and opinions expressed by the authors of published articles.
