Life cycle exposure of the frog Silurana tropicalis to arsenate: Steroid- and thyroid hormone-related genes are differently altered throughout development

摘要: Arsenic contaminates water surface and groundwater worldwide. Several studies have suggested that arsenic acts as an endocrine disruptor in mammalian non-mammalian species, although its chronic effect during development remains largely unknown. To address this question, life cycle exposures to 0, 0.3 0.8ppm of arsenate (pentavalent arsenic; As(V)) were performed the Western clawed frog (Silurana tropicalis) from gastrulae stage (developmental Nieuwkoop-Faber; NF12) until metamorphosis (NF66). Tissue samples collected at beginning feeding (NF46; whole body), sexual (NF56; liver), completion (NF66; liver gonadal mesonephros complex). Real-time RT-PCR analysis quantified decreases mRNA levels genes related estrogen- (estrogen receptor alpha aromatase), androgen- (androgen steroid 5-alpha-reductase type 2), cholesterol metabolism- (steroidogenic acute regulatory protein) NF46. Similarly, decreased 2 expression NF56 livers, but transcript increases observed for both estrogen steroidogenic protein stage. Given changes essential proper development, histological was carried out NF66 animals. Arsenate treatments did not alter sex ratio or produce testicular oocytes. On other hand, interfered with thyroid hormone-related transcripts NF66. Specifically, hormone beta deiodinase significantly reduced after treatment complex. This reduction gene expression, however, accompanied by any morphological measured. In summary, environmentally relevant concentrations As(V) altered steroidogenesis-, signaling- transcriptional varied among tissues developmental stages.