The effect of atrazine on gene expression of appetite‐regulating neurohormones in zebrafish

The herbicide atrazine is widely used in the U.S. and is one of the most common contaminants in groundwater. Previous studies have found effects of atrazine on growth, development, and appetite. To examine the mechanism through which atrazine affects appetite, we are studying the effects of atrazine exposure on appetite‐regulating neurohormones in the zebrafish, Danio rerio . We hypothesize that atrazine may inhibit appetite by disrupting the development or function of the neurons that secrete the orexigenic neurohormones neuropeptide Y (NPY) or ghrelin. To test this hypothesis, we exposed zebrafish to atrazine (0, 10 or 100 μg/L) for 15 days, beginning on day 20 post‐fertilization. We isolated total RNA from whole heads at the end of exposure, and five and nine weeks after end of exposure, from fed and overnight‐fasted fish. Probe‐based quantitative PCR (qPCR) assays were developed to measure levels of NPY and ghrelin mRNA. Preliminary results suggest that atrazine exposure suppressed the predicted fasting‐induced elevation of ghrelin mRNA, five weeks after exposure.