title: Cell junctional proteins in the human corpus luteum: changes during the normal cycle and after HCG treatment.
abstract: BACKGROUND
  Regulation of tissue remodelling and ovarian permeability by intercellular adhesion complexes may be involved in normal and pathological ovarian function. Therefore, the occurrence, distribution and hormonal control of the adherens junction protein vascular endothelial cadherin (VE-cadherin) and the tight junction proteins occludin and claudin in the human corpus luteum (CL) were investigated.
  
  
  METHODS
  CLs from patients undergoing hysterectomy for benign reasons were enucleated during early, mid- and late stages of the functional luteal phase and after HCG rescue in vivo. Immunostaining for occludin, claudins 1 and 5 and VE-cadherin was carried out on fixed tissue. Endothelial cells, granulosa lutein cells and theca lutein cells were identified by reference to serial sections immunostained for CD34, 17alpha-hydroxylase and 3beta-hydroxy-steroid-dehydrogenase. Quantitative analyses were performed using image analyses.
  
  
  RESULTS
  Occludin was localized to the plasma membrane of granulosa lutein cells and endothelial cells but was absent in theca lutein cells. Claudin 1 was exclusively localized to the plasma membrane of steroidogenic cells. Claudin 5 and VE-cadherin were only present in endothelial cells. After HCG administration in vivo, adherens and tight junction proteins were significantly down-regulated (P < 0.05).
  
  
  CONCLUSIONS
  The decrease of junctional proteins after HCG treatment suggests a hormonal control of tight and adherens junctions in the CL associated with tissue remodelling and an increase in luteal permeability during early pregnancy.
authors.affiliation: Department of Obstetrics and Gynecology, University of Ulm, Ulm, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Groten
authors.forename: H M
authors.initials: HM
authors.lastname: Fraser
authors.forename: W C
authors.initials: WC
authors.lastname: Duncan
authors.forename: R
authors.initials: R
authors.lastname: Konrad
authors.forename: R
authors.initials: R
authors.lastname: Kreienberg
authors.forename: C
authors.initials: C
authors.lastname: Wulff
mesh_terms: D015703:Antigens, CD / Q000378:metabolism*; D015820:Cadherins / Q000378:metabolism*; D006063:Chorionic Gonadotropin / Q000627:therapeutic use*; D062445:Claudin-1; D062507:Claudin-5; D003338:Corpus Luteum / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007365:Intercellular Junctions / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D008597:Menstrual Cycle / Q000187:drug effects* / Q000378:metabolism; D062793:Occludin; D000099152:Cadherin 5
chemical_list: D015703:Antigens, CD; D015820:Cadherins; D006063:Chorionic Gonadotropin; D062445:Claudin-1; D062507:Claudin-5; D008565:Membrane Proteins; D062793:Occludin; D000099152:Cadherin 5; C568108:CLDN1 protein, human; C107466:CLDN5 protein, human; C568985:OCLN protein, human