title: Perturbation of organogenesis by the herbicide atrazine in the amphibian Xenopus laevis.
abstract: BACKGROUND
  Exposure to anthropogenic chemicals during development can disrupt the morphogenesis of organ systems. Use of the herbicide atrazine has been debated in recent years because of its implicated, but poorly characterized, effects on vertebrates. Previous studies primarily examined the effects of atrazine exposure during metamorphosis or early developmental stages of amphibians.
  
  
  OBJECTIVE
  We sought to identify and characterize the susceptibility during the often-overlooked developmental stage of organ morphogenesis.
  
  
  METHODS
  We used a static renewal experimental treatment to investigate the effects of 10, 25, and 35 mg/L atrazine from early organ morphogenesis through the onset of tadpole feeding in the aquatic amphibian model system, Xenopus laevis. We quantified malformations of the body axis, heart, and intestine, as well as apoptosis in the midbrain and pronephric kidney.
  
  
  RESULTS
  We found a significant dose-dependent increase in the percentage of atrazine-exposed tadpoles with malformations of multiple tissues including the main body axis, circulatory system, kidney, and digestive system. Incidence of apoptotic cells also increased in the both midbrain and kidney of atrazine-exposed tadpoles.
  
  
  CONCLUSIONS
  Our results demonstrate that acute atrazine exposure (10-35 mg/L for < or = 48 hr) during early organ morphogenesis disrupts proper organ development in an amphibian model system. The concurrent atrazine-induced apoptosis in the pronephric kidney and midbrain begins to elucidate a mechanism by which atrazine may disrupt developmental processes in nontarget organisms.
authors.affiliation: Department of Biology, Tufts University, Medford, MA 02155, USA.
authors.forename: Jenny R
authors.initials: JR
authors.lastname: Lenkowski
authors.forename: J Michael
authors.initials: JM
authors.lastname: Reed
authors.forename: Lisa
authors.initials: L
authors.lastname: Deininger
authors.forename: Kelly A
authors.initials: KA
authors.lastname: McLaughlin
mesh_terms: D000818:Animals; D001280:Atrazine / Q000633:toxicity*; D019521:Body Patterning; D006540:Herbicides / Q000633:toxicity*; D007150:Immunohistochemistry; D038081:Organogenesis / Q000187:drug effects*; D014982:Xenopus laevis / Q000196:embryology*
chemical_list: D006540:Herbicides; D001280:Atrazine