Wednesday, March 3, 2010
Complete Feminization in Male Frogs due to the Use of Pesticide Atrazine
Scientist of the University of California, Berkeley and University of Cincinnati, have found that Atrazine (one of the most widely used pesticides and also a potent endocrine disruptor) exposure in adult male frogs cause complete feminization in the males. When male African Clawed Frogs (Xenopus laevis) were exposed to this pesticide, Ten percent of them developed into functional females that were able to copulate with unexposed males and produce viable eggs. The resulting larvae were all male when raised to metamorphosis and sampled, confirming that Atrazine-induced females were, in fact, chromosomal males. The Atrazine exposed males suffered from depressed testosterone, decreased breeding gland size, demasculinized laryngeal development, suppressed mating behavior, reduced spermatogenesis, and decreased fertility leading to complete feminization. Atrazine is also known to cause demasculinizes and feminizes exposed amphibian larvae, resulting in hermaphrodites.
Previous studies have shown that the Atrazine causes a reduction in sperm content in fishes like salmon, (Salmo salar) reptiles like caiman, (Caiman latirostris). The similarities between these previous findings in fish and in reptiles and the present findings in an amphibian suggest that the demasculinizing effects of atrazine are also not just species, genera, family specific but occur across vertebrate classes. The present findings exemplify that the role of Atrazine and other endocrine-disrupting pesticides, is likely a cause in the global amphibian declines.