title: Response of the amphibian tadpole (Xenopus laevis) to atrazine during sexual differentiation of the testis.
abstract: Xenopus laevis tadpoles were exposed for 48 h during sexual differentiation to atrazine at 21 microg/L under static laboratory conditions at 21+/-0.5 degrees C. After this exposure period, tadpoles were fixed and the kidney-gonad complex was microdissected. Quantitative histological analysis of the gonad revealed a 57% reduction in testicular volume among atrazine-exposed tadpoles. In addition, primary spermatogonial cell nests that represent germ cells for the life of the organism were reduced by 70%. Nursing cells, which provide nutritive support for the developing germ cells, had declined by 74%. Testicular resorption was observed among 70% and aplasia or failure of full development of the testis was recorded in 10% of the atrazine-exposed tadpoles. Because cell nests represent the pool of primordial germ cells for the reproductive life of the organism, the combined reduction in spermatogonial cell nests and nursing cells suggest that a pulse exposure to 21 microg/L of atrazine during sexual differentiation could significantly reduce reproduction during the reproductive life of these animals.
authors.affiliation: Department of Biology, Concordia University, Montreal, Quebec, Canada.
authors.forename: Luz
authors.initials: L
authors.lastname: Tavera-Mendoza
authors.forename: Sylvia
authors.initials: S
authors.lastname: Ruby
authors.forename: Pauline
authors.initials: P
authors.lastname: Brousseau
authors.forename: Michel
authors.initials: M
authors.lastname: Fournier
authors.forename: Daniel
authors.initials: D
authors.lastname: Cyr
authors.forename: David
authors.initials: D
authors.lastname: Marcogliese
mesh_terms: D000818:Animals; D001280:Atrazine / Q000009:adverse effects*; D006540:Herbicides / Q000009:adverse effects*; D007814:Larva / Q000254:growth & development; D008297:Male; D012733:Sex Differentiation / Q000187:drug effects*; D013094:Spermatozoa; D013737:Testis / Q000187:drug effects* / Q000254:growth & development* / Q000473:pathology; D014982:Xenopus laevis / Q000254:growth & development*
chemical_list: D006540:Herbicides; D001280:Atrazine