Response of the amphibian tadpole <i>Xenopus laevis</i> to atrazine during sexual differentiation of the ovary

Abstract

Abstract Xenopus laevis tadpoles (stage 56) were exposed to 21 μg/L atrazine under laboratory-controlled conditions in a static system. Following a 48-h exposure period at 21 ± 0.5°C during sexual differentiation, tadpoles were fixed, and the kidney-gonad complex was microdissected. Quantitative histological analysis revealed in a trazine-exposed ovaries a significant (p &amp;lt; 0.05) increase in frequency of secondary oogonia. Atresia, or oogonial resorption of both primary and secondary oogonia, also increased significantly (p &amp;lt; 0.05). The results suggest that these primary germ cells, which constitute the total number of germ cells in the ovary for the reproductive life of the organism, were reduced by 20% following a 48-h exposure period compared to 2% in controls.