Thyroid hormones are important for embryonic to larval transitory phase in zebrafish

Exposure to DE-71 alters thyroid hormone levels and gene transcription in the hypothalamic–pituitary–thyroid axis of zebrafish larvae

“…THs exert their effects by binding to specific TRs, which act as inducible ligand-activated transcription factors and play important roles in embryogenesis and larval development (Liu and Chan, 2002). In our study, exposure of fish embryos to DE-71 did not affect the transcription of TR gene.…”

“…Hence, substances interfering with TH activity can seriously compromise the normal development of the exposed species and may have profound consequences on their fitness and survival (Boas et al, 2006). In zebrafish, THs are necessary for the transition from the embryonic to larval stage and from the larval to the juvenile stage (Liu and Chan, 2002). Hence, TH disruption or reduced concentrations of THs during either of these transitions can cause growth retardation (Brown and Kim, 1995).…”

“…In non-mammalian vertebrates, e.g., amphibians and fish, corticotropin-releasing hormone (CRH) appears to stimulate TSH secretion (De Groef et al, 2006) and might therefore function as a common regulator of the thyroidal axis. THs act by binding to specific TRs and play important roles in the embryogenesis and larval development in the early stages of the fish life cycle (Liu and Chan, 2002). Endocrine disrupting chemicals (EDCs) have a direct impact on TH synthesis, transport, binding, and also interfere with the functioning of the thyroid system by inducing feedback mechanisms triggered by changes in the concentration of circulating THs (Kloas and Lutz, 2006).…”

Waterborne exposure to PFOS causes disruption of the hypothalamus–pituitary–thyroid axis in zebrafish larvae

“…Indeed, unchanged TH levels were often observed in fish exposed to environmental chemicals, and a number of other studies have noted that plasma TH levels may be a poor predictive indicator of disruption of the thyroid axis (Bradford et al, 2005;Li et al, 2009;Morgado et al, 2009). In zebrafish, THs are necessary for embryonic to larval transition and larval to juvenile transition (Liu and Chan, 2002). Hence, if TH disruption occurs during either transition, growth retardation might occur (Brown et al, 1997).…”

Epidermal transient down‐regulation of retinol‐binding protein 4 and mirror expression of apolipoprotein Eb and estrogen receptor 2a during zebrafish fin and scale development

“…This molecule is a goitrogen in zebrafish larva (Elsalini and Rohr, 2003). It has been demonstrated in zebrafish that thyroid hormones are important for the embryo-larva transition phase (Liu and Chan, 2002) and critical during the larva-juvenile transition (Brown, 1997). Thyroid disruptors inhibit fin and scale morphogenesis and skin pigment differentiation (Brown, 1997, Van der Ven et al, 2006.…”