title: Effects of atrazine on metamorphosis, growth, and gonadal development in the green frog (Rana clamitans).
abstract: Embryos of the green frog (Rana clamitans) were collected from the field and exposed to 1 of 6 water-borne treatments for 273 d (mid July 2001 to mid April 2002). The treatments were 0, 10, or 25 microg/L atrazine, 0.005% ethanol (EtOH), or 0.1 mg/L estradiol or dihydrotestosterone carried in 0.005% EtOH. Treatments were applied in a static renewal system with a 50% test solution replacement approximately every 3 d. Following the exposure period, tadpoles were reared in freshwater until metamorphosis or until study termination (at d 506). Time to initiate and complete metamorphosis, stage-specific mortality, length and weight at metamorphosis, and gross morphology and histology of the gonads were examined. At environmentally relevant concentrations, atrazine did not consistently affect growth or metamorphosis. Compared to controls, the length of the larval period was greater in tadpoles exposed to 10 microg/L atrazine. However, the length of the larval period was not markedly different between tadpoles in the control and 25 microg/L atrazine treatments. Neither gross gonadal morphology nor histopathology of the gonads in postmetamorphic frogs was significantly altered in response to atrazine exposure. This study provides evidence that environmentally relevant concentrations of atrazine do not adversely affect the growth or reproductive development of R. clamitans.
authors.affiliation: Department of Zoology, National Food Safety and Toxicology Center, Institute for Environmental Toxicology, Michigan State University, East Lansing, Michigan, USA. kcoady@entrix.com
authors.forename: Katherine
authors.initials: K
authors.lastname: Coady
authors.forename: Margaret
authors.initials: M
authors.lastname: Murphy
authors.forename: Daniel
authors.initials: D
authors.lastname: Villeneuve
authors.forename: Markus
authors.initials: M
authors.lastname: Hecker
authors.forename: Paul
authors.initials: P
authors.lastname: Jones
authors.forename: James
authors.initials: J
authors.lastname: Carr
authors.forename: Keith
authors.initials: K
authors.lastname: Solomon
authors.forename: Ernest
authors.initials: E
authors.lastname: Smith
authors.forename: Glen
authors.initials: G
authors.lastname: Van Der Kraak
authors.forename: Ronald
authors.initials: R
authors.lastname: Kendall
authors.forename: John
authors.initials: J
authors.lastname: Giesy
mesh_terms: D000818:Animals; D001280:Atrazine / Q000633:toxicity*; D005260:Female; D006066:Gonads / Q000187:drug effects* / Q000254:growth & development; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D008297:Male; D008675:Metamorphosis, Biological / Q000187:drug effects*; D011898:Ranidae; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; D001280:Atrazine