title: Expression and activation of mitogen-activated protein kinase in the human endometrium during the menstrual cycle.
abstract: OBJECTIVE
  The purpose of this study was to investigate the fluctuation of expression and activation of mitogen-activated protein kinase in normal human endometrium throughout the menstrual cycle.
  
  
  METHODS
  Thirty-three normal endometrial tissues were obtained from fertile women who had undergone hysterectomies for reasons other than endometrial disease. Extracellular signal-regulated kinase, -1, and -2 expression were studied by immunohistochemistry. Moreover, extracellular signal-regulated kinase activity was analyzed by gel kinase assay.
  
  
  RESULTS
  Western blotting analysis with anti-pan-extracellular signal-regulated kinase antibody mainly demonstrated an immunoreactive band of 42 kd that corresponded to extracellular signal-regulated kinase 2 in the endometrium. The expression of extracellular signal-regulated kinase 2 tended to increase in the secretory phase. Immunohistochemical analysis for extracellular signal-regulated kinase 1 in endometrial sections revealed a weak staining of glands and almost no staining of stromal cells. Immunohistochemical analysis for extracellular signal-regulated kinase 2 in endometrial sections revealed a distinct staining of glands in both proliferative and secretory phases and a weak staining of stromal cells. Although the intensity of staining for extracellular signal-regulated kinase 2 in stromal cells did not change during the secretory phase, in the glands the extracellular signal-regulated kinase 2 was highly stained in the mid-to-late secretory phase. In gel kinase assay revealed that extracellular signal-regulated kinase activity was increased significantly in the mid-to-late secretory phase.
  
  
  CONCLUSIONS
  Expression and activation of extracellular signal-regulated kinase in the human endometrium was increased particularly during the secretory phase. We suggest that fluctuation of extracellular signal-regulated kinase in the human endometrium may be induced by ovarian steroid hormones.
authors.affiliation: Department of Obstetrics and Gynecology, Seirei Hamamatsu General Hospital, Hamamatsu, Japan.
authors.forename: Tomoya
authors.initials: T
authors.lastname: Ozaki
authors.forename: Kentaro
authors.initials: K
authors.lastname: Takahashi
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Kanasaki
authors.forename: Kohji
authors.initials: K
authors.lastname: Miyazaki
mesh_terms: D000328:Adult; D004717:Endometrium / Q000201:enzymology*; D004789:Enzyme Activation; D005260:Female; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D007527:Isoenzymes / Q000378:metabolism; D008183:Luteal Phase / Q000378:metabolism; D008597:Menstrual Cycle / Q000378:metabolism*; D008875:Middle Aged; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D013194:Staining and Labeling
chemical_list: D007527:Isoenzymes; D020928:Mitogen-Activated Protein Kinases