Upregulation of estrogen receptor subtypes and vitellogenin mRNA in cinnamon clownfish Amphiprion melanopus during the sex change process: Profiles on effects of 17β-estradiol

Regulation of reproduction- and biomarker-related gene expression by sex steroids in the livers and ovaries of adult female western mosquitofish (Gambusia affinis)

“…It is well known that Vtg mRNA expression is induced in oviparous fish species in response to estrogens by an ER-mediated pathway (Kim et al, 2010). It is not known however, whether each ER isoform contributes equally to the transcriptional regulation of Vtg genes in many species.…”

“…The most commonly observed impacts of steroids on fish are the induction of the female specific vitellogenins (Vtgs) mainly by estrogens (Lange et al, 2002;Leusch et al, 2005;Kim et al, 2010). Feminization of male fish has been reported in rivers of many regions (Matthiessen et al, 2002;Kolok et al, 2007;Xie et al, 2010).…”

“…Fish Vtgs have been divided into three types based on primary structure. The two Vtg types that possess two lipovitellin domains and one phosvitin domain are classified as VtgA and VtgB, and the third type is classified as VtgC, which contains no polyserine phosvitin domain (Henry et al, 2009;Kim et al, 2010). Generally, Vtgs are undetectable in male and immature female fish unless exposure to exogenous estrogenic compounds has occurred.…”

“…One route of action of steroid hormones is mediated through nuclear hormone receptors, which are activated by steroid ligands and regulate gene expression by interacting with specific DNA sequences upstream of their target genes (Kim et al, 2010;Smolinsky et al, 2010). As a consequence, nuclear receptors play key roles in reproduction and sexual differentiation (Seo et al, 2006).…”

“…ERs were localized in both sexes in numerous tissues and are able to modify transcriptional rates of estrogen response genes through binding as dimers to estrogen response elements (EREs) in the promoter regions of those target genes (Janošek et al, 2006;Pinto et al, 2006;Kim et al, 2010). Until now, two distinct types of ERs (called ERα and ERβ) have been isolated in several fish species including largemouth bass (Sabo-Attwood et al, 2004), mosquitofish (Katsu et al, 2007), tilapia (Esterhuyse et al, 2010), and in cinnamon clownfish (Kim et al, 2010). Role of the androgen receptor (AR) in male organism is very similar to that of estrogen receptor in females (Janošek et al, 2006;Smolinsky et al, 2010).…”