View article

Adult African clawed frogs (Xenopus laevis) were collected from a corn‐growing region (CGR) and a non‐corn‐growing region (NCGR) with different exposure profiles for atrazine and related triazines. Physical, chemical, and biological parameters from the catchment areas were also measured. Frogs were surveyed for possible effects of exposure to triazine herbicides on plasma testosterone (T) and estradiol (E2) titers, gonadal aromatase activity, and gonad growth (GSI). Concentrations of both T and E2 varied among locations and were correlated to some accessory factors, such as pH, several ions, and metals. Greatest median plasma T concentrations (males: 19 ng/ml; females: 16 ng/ml) occurred in frogs inhabiting NCGR as compared to those from the CGR (males: 4 ng/ml; females: 1 ng/ml). Median E2 concentrations were also greater in frogs collected from the NCGR (males: 3 ng/ml; females: 28 ng/ml) than …