title: Estrogenic effects of dissolved organic matter and its impact on the activity of 17β-estradiol.
abstract: OBJECTIVE
  The ubiquitous dissolved organic matter (DOM) is actually not inert as we always think, and the hormone-like effects of DOM have been reported. The objective of this study was to investigate the estrogenic effects of DOM and its impact on the activity of the natural estrogen 17β-estradiol (E2).
  
  
  METHODS
  DOM of three different sources, HA sodium salt, Suwannee River natural organic matter (NOM), and Nordic Reservoir NOM, were used. The estrogenic activity was detected by using the yeast estrogen screen (YES) assay. Estrogenic effects of DOM without and after solar irradiation were tested. Influences on the action of E2 by DOM were also investigated.
  
  
  RESULTS
  No direct estrogenic effects of the DOM used were observed in the YES assay. However, the estrogenic activities after 24 h of irradiation increased to 0.0288, 0.0178, and 0.0195 μM of E2 equivalents for HA sodium salt, Suwannee River NOM, and Nordic Reservoir NOM, respectively. After incubation of DOM, the estrogenic activity of E2 was increased by low concentrations (8.33 and 83.3 μM) of DOM while decreased by higher concentrations (8.33 × 10(2) and 8.33 × 10(3) μM) of DOM.
  
  
  CONCLUSIONS
  Though direct estrogenic effects of DOM were not observed, increase in the estrogenic activity of DOM after irradiation was significant. DOM shows amphoteric influence on the natural estrogen E2, which depends on the concentration of DOM used. Because of its ubiquity, DOM may be of great ecological significance, playing an important role in regulating the reproduction of aquatic organisms.
authors.affiliation: College of Environmental and Resource Sciences, Zhejiang University, 268 Kaixuan Road, Hangzhou 310029, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
authors.forename: Chaofeng
authors.initials: C
authors.lastname: Shen
authors.forename: Xianjin
authors.initials: X
authors.lastname: Tang
authors.forename: Chen
authors.initials: C
authors.lastname: Chen
authors.forename: Yingxu
authors.initials: Y
authors.lastname: Chen
mesh_terms: D001682:Biological Availability; D004784:Environmental Monitoring / Q000379:methods; D004958:Estradiol / Q000737:chemistry*; D047628:Estrogen Receptor alpha / Q000378:metabolism; D004967:Estrogens / Q000737:chemistry*; D009930:Organic Chemicals / Q000737:chemistry*; D052638:Particulate Matter / Q000737:chemistry; D045483:Rivers / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D047628:Estrogen Receptor alpha; D004967:Estrogens; D009930:Organic Chemicals; D052638:Particulate Matter; D014874:Water Pollutants, Chemical; D004958:Estradiol