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

In the present study, we investigated the expression pattern of estrogen receptors (esr) and vitellogenin (vtg) mRNA in the gonads and liver during sex change in cinnamon clownfish by using quantitative polymerase chain reaction. We divided gonadal development during the sex change from male to female into 3 stages (mature male, male at 90 days after removing female, and mature female) and investigated esr and vtg mRNA expressions during the sex change. With female, the esr and vtg mRNA expressions increased. In western blot analysis, Esr1 protein was detected only in the ovaries of female cinnamon clownfish. Also, to understand the effect of 17β-estradiol (E2), we investigated the esr and vtg mRNA expression patterns in the gonads and liver, and the changes in plasma E2 level after E2 injection. E2 treatment increased both mRNA expression levels of esr and vtg and plasma E2 levels. The present study describes the molecular characterization of esr subtypes and the interactions between esr and vtg after E2 treatment in cinnamon clownfish.