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Does Atrazine Affect Larval Development and Sexual Differentiation of South African Clawed Frogs?
Author(s) -
Kloas Werner,
Lutz Ilka,
Urbatzka Ralph,
Springer Tim,
Krueger Hank,
Wolf Jeffrey,
Holden Larry,
Hosmer Alan
Publication year - 2009
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.2009.04456.x
Subject(s) - sexual differentiation , aromatase , xenopus , medicine , feminization (sociology) , endocrinology , luteinizing hormone , biology , atrazine , estrogen , hormone , amphibian , endocrine system , follicle stimulating hormone , pesticide , ecology , biochemistry , social science , cancer , sociology , breast cancer , gene
The potential impact of atrazine (ATZ) on gonadal malformations in larval Xenopus laevis has been controversially discussed, and a hypothesis has been generated that ATZ might induce the estrogen‐synthesizing enzyme aromatase, leading to feminization or demasculinization. Recently, extensive long‐term studies clearly indicate that no adverse effect of ATZ on larval development and sexual differentiation could be found. Therefore, to determine potential transient impacts of ATZ on sexual differentiation processes, short‐term exposures were conducted using tadpoles treated for 4 days with ATZ at 25 μg/L. The expression levels of the key players for sexual differentiation in amphibians were determined in the brain, assessing aromatase, 5α‐reductase type 1 (S1) and type 2 (S2), and the gonadotropins luteinizing hormone and follicle‐stimulating hormone, and in the gonads, measuring aromatase, S1, and S2, by means of quantitative RT‐PCR. No significant changes in any of these parameters have been found, implicating, in accordance with recent long‐term exposures, that no aromatase induction by ATZ could be observed, and it seems likely that no further endocrine mechanism of ATZ affecting sexual differentiation in X. laevis exists.