Document Detail

Location of insulin receptors in the placenta and its progenitor tissues.
MedLine Citation:
PMID:  9260838     Owner:  NLM     Status:  MEDLINE    
The insulin receptor gene is constitutively expressed, so the presence of insulin receptor proteins might be expected on all mammalian tissues, with the plasma membrane as the predominant site of receptor location. Results reviewed here indicate that insulin receptors are also present in all placental tissues and the placenta's progenitor tissues and cells, i.e., oocytes, spermatozoa, and preimplantation embryos, in most of the species studied. Receptor densities, however, vary among individual cells and cell types and at various developmental stages. Three aspects deserve emphasis. 1) In human placenta, the insulin receptor distribution pattern is characterized by a spatiotemporal change between first trimester and term. At the beginning of pregnancy, insulin receptors are found predominantly on the maternal side (apical membrane of syncytiotrophoblast, low density on cytotrophoblast); at term, however, they are on the fetal side (lining the fetal vessels). This suggests that, in the first trimester, maternal insulin regulates insulin-dependent processes, whereas, at term, it must be fetal insulin mainly controlling these processes. 2) The majority of insulin receptors is expressed on structures that are currently assumed to drive placental growth, i.e., syncytial sprouts and mesenchymal villi in first-trimester placentas and fetal endothelium at term. Therefore, we hypothesize a growth-promoting function, among others, of insulin on the placenta. 3) At present, no histologic evidence is available to demonstrate insulin receptors in structures commonly associated with receptor-mediated endocytosis. Whether placental insulin receptors are internalized, therefore, awaits clarification.
G Desoye; M Hartmann; C J Jones; H J Wolf; G Kohnen; G Kosanke; P Kaufmann
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Review    
Journal Detail:
Title:  Microscopy research and technique     Volume:  38     ISSN:  1059-910X     ISO Abbreviation:  Microsc. Res. Tech.     Publication Date:    1997 Jul 1-15
Date Detail:
Created Date:  1997-09-18     Completed Date:  1997-09-18     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  9203012     Medline TA:  Microsc Res Tech     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  63-75     Citation Subset:  IM    
Department of Obstetrics and Gynecology, University of Graz, Austria.
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MeSH Terms
Cell Division
Chorionic Villi / ultrastructure
Placenta / chemistry*,  ultrastructure
Receptor, Insulin / analysis*,  metabolism
Reg. No./Substance:
EC, Insulin

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