Alterations to the vision-associated transcriptome of zebrafish (Danio rerio) following developmental norethindrone exposure

•Developmental (ELS) norethindrone (NET) exposure alters zebrafish gene expression.•RNAseq data indicates significant effects on phototransduction and eye development.•Mean retinal layer diameter was not affected by NET exposure in ELS zebrafish.•NET exposure may alter transition to adult photoreceptor mosaic pattern in ELS fish.•Glycerolipid/steroid metabolism, protein processing pathways also affected by NET. Synthetic sex steroids, like the synthetic progestin norethindrone (NET), can affect a wide variety of biological processes via highly conserved mechanisms. NET is prevalent in surface waters, yet the sub-lethal effects of NET exposure are not are net yet well characterized in aquatic biota. A few targeted gene expression and behavioral studies have concluded that NET affects the vision of adult fish; however, early life stage (ELS) fish are often more sensitive to contaminants. Furthermore, many species of fish rely heavily on visual perception for survival during development. The goal of the present study was to characterize the effects of developmental exposure to environmentally relevant concentrations of NET on the visual system of ELS zebrafish, using transcriptomics and histological methods. Results indicate that exposure to relatively low levels of NET in aquatic systems may be sufficient to affect the visual function of developing fish.