title: Atrazine induces complete feminization and chemical castration in male African clawed frogs (Xenopus laevis).
abstract: The herbicide atrazine is one of the most commonly applied pesticides in the world. As a result, atrazine is the most commonly detected pesticide contaminant of ground, surface, and drinking water. Atrazine is also a potent endocrine disruptor that is active at low, ecologically relevant concentrations. Previous studies showed that atrazine adversely affects amphibian larval development. The present study demonstrates the reproductive consequences of atrazine exposure in adult amphibians. Atrazine-exposed males were both demasculinized (chemically castrated) and completely feminized as adults. Ten percent of the exposed genetic males developed into functional females that copulated with unexposed males and produced viable eggs. Atrazine-exposed males suffered from depressed testosterone, decreased breeding gland size, demasculinized/feminized laryngeal development, suppressed mating behavior, reduced spermatogenesis, and decreased fertility. These data are consistent with effects of atrazine observed in other vertebrate classes. The present findings exemplify the role that atrazine and other endocrine-disrupting pesticides likely play in global amphibian declines.
authors.affiliation: Laboratory for Integrative Studies in Amphibian Biology, Department of Integrative Biology, University of California, Berkeley, CA 94720-3140, USA. tyrone@berkeley.edu
authors.forename: Tyrone B
authors.initials: TB
authors.lastname: Hayes
authors.forename: Vicky
authors.initials: V
authors.lastname: Khoury
authors.forename: Anne
authors.initials: A
authors.lastname: Narayan
authors.forename: Mariam
authors.initials: M
authors.lastname: Nazir
authors.forename: Andrew
authors.initials: A
authors.lastname: Park
authors.forename: Travis
authors.initials: T
authors.lastname: Brown
authors.forename: Lillian
authors.initials: L
authors.lastname: Adame
authors.forename: Elton
authors.initials: E
authors.lastname: Chan
authors.forename: Daniel
authors.initials: D
authors.lastname: Buchholz
authors.forename: Theresa
authors.initials: T
authors.lastname: Stueve
authors.forename: Sherrie
authors.initials: S
authors.lastname: Gallipeau
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001280:Atrazine / Q000633:toxicity*; D004785:Environmental Pollutants / Q000633:toxicity; D005260:Female; D005262:Feminization / Q000097:blood / Q000139:chemically induced* / Q000503:physiopathology; D005298:Fertility / Q000187:drug effects; D006540:Herbicides / Q000633:toxicity; D007814:Larva / Q000187:drug effects / Q000502:physiology; D007830:Larynx / Q000187:drug effects / Q000473:pathology; D008297:Male; D012733:Sex Differentiation / Q000187:drug effects*; D012726:Sexual Behavior, Animal / Q000187:drug effects; D013091:Spermatogenesis / Q000187:drug effects; D013737:Testis / Q000187:drug effects / Q000473:pathology; D013739:Testosterone / Q000097:blood; D014982:Xenopus laevis / Q000502:physiology*
chemical_list: D004785:Environmental Pollutants; D006540:Herbicides; D013739:Testosterone; D001280:Atrazine