Document Detail

Expression of epidermal growth factor and its receptor in equine placental tissues.
MedLine Citation:
PMID:  9538329     Owner:  NLM     Status:  MEDLINE    
Northern blot and in situ hybridization techniques have demonstrated a marked increase in mRNA encoding epidermal growth factor (EGF) in the endometrium of mares, coincident with the start of interdigitation between the allantochorion and endometrium during placentation. In the present study, the unusually high EGF expression in the epithelium of the endometrial glands was shown to be maintained until at least day 250 of gestation (term = 320-340 days) in mares carrying normal horse conceptuses. However, in mares carrying failing donkey-in-horse pregnancies created by embryo transfer, EGF expression was severely retarded in those areas of the endometrium that were heavily infiltrated with lymphocytes and which showed a failure of placental development. Specific receptors for EGF were also detected in tissue homogenates from pregnant mares using 125I-labelled human EGF. Binding was high in the fetal membranes (allantochorion), both before implantation (days 30-34) and in the fully developed placenta (days 150-250), and was equivalent to the level of binding to homogenates of adult liver and kidney. Binding was much reduced in endometrial homogenates before implantation and from non-pregnant mares but increased after implantation to reach values equivalent to those exhibited by the fetal membranes. Scatchard analysis of displacement curves indicated a single class of high-affinity binding sites in the fetal membranes and pregnant endometrium sampled at day 150 of pregnancy and chemical cross-linking of the receptor-125I-labelled EGF complexes in fetal membranes revealed two radiolabelled bands of 170 kDa and 150 kDa. A large excess of insulin-like growth factor I (IGF-I) failed to displace any labelled EGF from the tissue homogenates. The marked and sustained upregulation of endometrial EGF expression during pregnancy in mares, and the presence of EGF receptors in the fetal allantochorion and maternal endometrium, suggest a possible role for EGF in the marked growth of these two tissues during placentation in equids.
S N Lennard; C Gerstenberg; W R Allen; F Stewart
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of reproduction and fertility     Volume:  112     ISSN:  0022-4251     ISO Abbreviation:  J. Reprod. Fertil.     Publication Date:  1998 Jan 
Date Detail:
Created Date:  1998-04-16     Completed Date:  1998-04-16     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  0376367     Medline TA:  J Reprod Fertil     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  49-57     Citation Subset:  IM    
University of Cambridge, Department of Clinical Veterinary Medicine, Babraham, UK.
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MeSH Terms
Allantois / metabolism
Blotting, Northern
Chorion / metabolism
Embryo Transfer
Epidermal Growth Factor / genetics*
Gene Expression
Horses / metabolism*
In Situ Hybridization
Placenta / metabolism*
Pregnancy, Animal / metabolism*
RNA, Messenger / analysis
Receptor, Epidermal Growth Factor / genetics*
Grant Support
Reg. No./Substance:
0/RNA, Messenger; 62229-50-9/Epidermal Growth Factor; EC, Epidermal Growth Factor

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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