Molecular cloning of zebrafish and medaka vitellogenin genes and comparison of their expression in response to 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)

“…The present results showed a significant increase of both VtgA and VtgB mRNA expression by E2 treatment in the livers of mosquitofish compared with the controls. This is in agreement with previous studies which have demonstrated the induction of Vtg mRNA expression in response to E2 in several fish species (Tong et al, 2004;Leusch et al, 2005). Vtg genes are a very sensitive target for E2.…”

Expression Analysis of Estrogen-responsive Genes Vitellogenin 1 and 2 in Liver of Male Medaka (Oryzias latipes) Exposed to Selective Ligands of Estrogen Receptor Subtypes

“…[8][9][10][11] Therefore, estrogen apparently drives the induction of VTG through the ER signaling pathway, and VTG is a sensitive biomarker for detecting estrogenic and/or anti-estrogenic chemical activities. [12][13][14] There are several common in vitro and in vivo VTG assays using fish; in vitro assays typically use cultured liver cells and in vivo assays use whole fish bred in test solutions. [15][16][17][18] These assays use VTG mRNA or VTG protein as an index.…”

Effects of adrenergic agents on the expression of zebrafish (Danio rerio) vitellogenin Ao1

“…It has been suggested that, in teleosts, VTG genes are primarily expressed in the liver (Wang et al, 2000;Islinger et al, 2003;Tong et al, 2004;Wang et al, 2005;Mikawa et al, 2006). With this assumption, heart tissue has often been overlooked to test for vtg mRNA levels in previous reports on medaka vtgAb, zebrafish vtgAo1, vtgC or many other newly cloned fish VTG transcripts (Wang et al, 2000;Islinger et al, 2003;Van der Ven et al, 2003;Tong et al, 2004;Wang et al, 2005;Jung et al, 2005;Sawaguchi et al, 2005;Mikawa et al, 2006).…”

“…With this assumption, heart tissue has often been overlooked to test for vtg mRNA levels in previous reports on medaka vtgAb, zebrafish vtgAo1, vtgC or many other newly cloned fish VTG transcripts (Wang et al, 2000;Islinger et al, 2003;Van der Ven et al, 2003;Tong et al, 2004;Wang et al, 2005;Jung et al, 2005;Sawaguchi et al, 2005;Mikawa et al, 2006). One exception is the report by Mikawa et al (2006) that indicated that vtgAe1 expression is not expressed in the heart tissue of the Japanese conger.…”

“…Fish VTGs are usually considered to be the precursors of major egg yolk proteins. They are produced in the female liver under the control of estrogen or 17β-estradiol (E 2 ), and then are secreted into the bloodstream, and finally incorporated into the oocytes, and subsequently accumulated as egg yolk proteins (Chen et al, 1997;Tong et al, 2004;Finn and Kristoffersen, 2007). Fish VTGs are normally present only in the plasma of adult female fish.…”