Meeting Abstract
Exposure to herbicides may influence development through disruption of endocrine processes. Butachlor is an herbicide used commonly in rice agriculture that influences thyroid hormone function. To better understand the potential consequences of butachlor exposure, we examined the effect of butachlor on development of the thyroid gland in cane toad tadpoles, Rhinella marina. Eggs, tadpoles, or eggs and tadpoles were exposed to 0, 0.002, 0.02, and 0.2 mg/L butachlor, and thyroid gland histology was evaluated via imaging to determine a total follicle count, follicle and colloid area, and thyrocyte height and width. Butachlor decreased the number of thyroid follicles in animals exposed at any life stage; however, exposure only influenced thyrocyte width and height at the lowest dose in animals exposed at the egg stage. Butachlor exposure had no effect on thyroid follicle size. Our results suggest that butachlor affects thyroid gland development without influencing shifts in follicular morphology. Future studies should measure thyroid hormone levels in butachlor exposed tadpoles.
