Bufo gargarizan is a wide distributed amphibian species
throughout the agricultural landscapes in China. B. gargarizan has
been used as a model animal for detecting chemicals effects in
our laboratory (Xia et al., 2012; Zhao et al., 2013). Since the contribution
of nitrate to alteration of thyroid hormones signaling pathways
in amphibians is unknown, we use a multidisciplinary
approach to evaluate the TH-disruption of nitrate on B. gargarizan
larvae development. The aim of present study was to investigate
the effects of environmentally-relevant concentrations of nitrate
on the timings of metamorphosis, mortality, body size and body
mass at metamorphosis in B. gargarizan. In addition, levels of T4
and T3 were measured to assess changes in hormone production
of thyroid. Moreover, thyroid gland histological analysis was used
as a biomarker for thyroid damages. Finally, RT-qPCR was utilized
to determine whether nitrate affects thyroid hormones homeostasis
by examining the Dio2 and Dio3 expression in peripheral tissues,
including intestine, hind-limb and tail.