title: Evidence of inhibin/activin subunit betaC and betaE synthesis in normal human endometrial tissue.
abstract: BACKGROUND
  Inhibins are important regulators of the female reproductive system. Recently, two new inhibin subunits betaC and betaE have been described, although it is unclear if they are synthesized in normal human endometrium.
  
  
  METHODS
  Samples of human endometrium were obtained from 82 premenopausal, non-pregnant patients undergoing gynecological surgery for benign diseases. Endometrium samples were classified according to anamnestic and histological dating into proliferative (day 1-14, n = 46), early secretory (day 15-22, n = 18) and late secretory phase (day 23-28, n = 18). Immunohistochemical analyses were performed with specific antibodies against inhibin alpha (n = 81) as well as inhibin betaA (n = 82), betaB (n = 82), betaC (n = 74) and betaE (n = 76) subunits. RT-PCR was performed for all inhibin subunits. Correlation was assessed with the Spearman factor to assess the relationship of inhibin-subunits expression within the different endometrial samples.
  
  
  RESULTS
  The novel inhibin betaC and betaE subunits were found in normal human endometrium by immunohistochemical and molecular techniques. Inhibin alpha, betaA, betaB and betaE subunits showed a circadian expression pattern, being more abundant during the late secretory phase than during the proliferative phase. Additionally, a significant correlation between inhibin alpha and all inhibin beta subunits was observed.
  
  
  CONCLUSIONS
  The differential expression pattern of the betaC- and betaE-subunits in normal human endometrial tissue suggests that they function in endometrial maturation and blastocyst implantation. However, the precise role of these novel inhibin/activin subunits in human endometrium is unclear and warrants further investigation.
authors.affiliation: Ludwig-Maximilians-University Munich, 1st Department of Obstetrics and Gynecology, Maistrasse 11, 80337 Munich, Germany. ioannis.mylonas@med.uni-muenchen.de
authors.forename: Ioannis
authors.initials: I
authors.lastname: Mylonas
authors.forename: Ansgar
authors.initials: A
authors.lastname: Brüning
authors.forename: Naim
authors.initials: N
authors.lastname: Shabani
authors.forename: Susanne
authors.initials: S
authors.lastname: Kunze
authors.forename: Markus S
authors.initials: MS
authors.lastname: Kupka
mesh_terms: D002940:Circadian Rhythm; D004717:Endometrium / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D028322:Inhibin-beta Subunits / Q000096:biosynthesis*; D008183:Luteal Phase / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: C504186:INHBC protein, human; C504183:INHBE protein, human; D028322:Inhibin-beta Subunits