PARENT SESSION

PM15 Biomarkers
Exhibit Hall
8:00 AM - Monday

(PM242) Effects of atrazine and estradiol on plasma sex steroid concentrations in male adult Xenopus laevis.

Hecker, M.¹, Murphy, M.¹, Jones, P.¹, Solomon, K.², van der Kraak, G.², Kendall, R.³, Giesy, J.¹, ¹ Michigan State University, East Lansing, Michigan, USA² University of Guelph, Guelph, Ontario, Canada³ Texas Tech University, Lubbock, Texas, USA

ABSTRACT- Adult male African clawed frogs (Xenopus laevis) were exposed to either 0.1g/L estradiol (E2) or atrazine (1, 10, 25, 100 or 200g/L). Plasma was analyzed for the sex steroid hormones testosterone (T) and estradiol (E2). In addition, exposure conditions (group exposure vs individual exposure) were tested as a potential factor affecting plasma hormone titers. While exposure to E2 resulted into a significant decrease in plasma T (Mann-Whitney U: p<0.001) and an increase in plasma E2 (Mann-Whitney U: p<0.001), no significant effects could be observed for all of the above concentrations of atrazine. In general, plasma steroid concentrations were highly variable within and among treatments. Variability within the different exposure groups was slightly greater for the individually housed frogs when compared to group exposures. Regardless of the great variability exposure to the positive control E2 resulted in significant effects on plasma sex steroid concentrations indicating the functionality of the test system. Thus it can be concluded that atrazine is unlikely to exhibit estrogen like actions as hypothesized previously by other authors.

Key words: amphibians, atrazine, endocrine disruption , sex steroids