In vivo estrogen induction of hepatic estrogen receptor mRNA and correlation with vitellogenin mRNA in rainbow trout

Abstract

SummaryWe have previously described the cloning, sequencing and in vitro expression of a full-length rainbow trout estrogen receptor cDNA (rtER cDNA). This full cDNA randomly labelled was used to study the estrogen induction of hepatic rtER mRNA in correlation with vitellogenin (Vg) mRNA in different physiolo~cal situations.In this paper, we show that in the liver two mRNA species are under hormonal control and their level increases about g-fold after estrogen stimulation.These two mRNAs are expressed and induced in the liver as early as the hatching stage in correlation with the expression of Vg mRNA. A long-term analysis of rtER mRNA after estradiol (E2) injection shows a transient induction of the nuclear ER and its mRNA which recover to the basal level after 2 weeks. Nevertheless, a memory effect was observed on the expression of the Vg gene which does not appear to be directly related to the estrogen receptor level.

Absence of direct regulation of prolactin cells by estradiol-17β in rainbow trout (Oncorhynchus mykiss)

“…Interestingly, comparison between immature and mature female rainbow trout showed no increase in the number of grains per PPD or PI cells suggesting that, expression of the ER gene in the pituitary is not strongly regulated by E,. This is clearly different from what has been shown in trout liver by Pakdel et al (1991). Different regulation of rtER mRNA levels according to the cell type in the brain and in the pituitary of rainbow trout has been suggested by Salbert et al (1991).…”

Early regulation of brain aromatase (cyp19a1b) by estrogen receptors during zebrafish development

“…This is further suggested by the fact that the liver esr1 signal overlaps prox1 mRNA (data not shown) an early marker of embryonic liver in zebrafish (Zhao et al, 2007). Expression of esr1 in the liver is likely related to the fact that this organ is an important target tissue for E2 in all oviparous species (Pakdel et al, 1991;Flouriot et al, 1996).…”

Quantitative real-time RT-PCR for determination of vitellogenin mRNA in so-iuy mullet (Mugil soiuy)

“…1 Collection site of the so-iuy mullet in Liaodong Bay, Bohai Bay, and NanDaiHe in the Bo Sea, and a control site in north China mixed briefly and placed in ice immediately. Syntheses of cDNA were carried out in a 5-μL reaction mixture containing RNase-free water; 1×TaqMan RT buffer; 5.5 mM magnesium chloride; 0.5 mM each of dATP, dGTP, dCTP, and dTTP; 2.5 μM Oligo(dT) 18 ; 0.4 U/μL RNase inhibitor; and 1.25 U/μL of MultiScribe reverse rranscriptase. The RT reaction was carried out for 5 min at 25°C, 5 min at 42°C, and 45 min at 50°C and then inactivated for 15 min at 70°C.…”

“…Because the Vtg mRNA expression after E2 injection even at low dose is obvious, however, such variation of β-actin copies can be neglected for the evaluation of Vtg mRNA expression. Published reports [17,18] have suggested that the time course for maximum induction of Vtg mRNA ranges from 16 h to 15 days depending on the species, route of exposure, and doses used. Despite the fact that the optimal time point for mRNA induction may not have been used in the present study, Vtg mRNA expression was induced after single injection for 5 days.…”