Vitellogenin gene expression in primary culture of male rainbow trout hepatocytes

Vaillant, Colette; Guellec, Catherine Le; Pakdel, Farzad; Valotaire, Yves

doi:10.1016/0016-6480(88)90148-7

Cited by 74 publications

(34 citation statements)

References 21 publications

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“…In contrast to a previous report on E2 regulation of vitellogenin in male trout [25], we found that a second injection of E2, 2 weeks after a priming treatment did not induce a greater or more immediate response to this hormone. In vitro, the vitellogenin response to E2 was larger and faster than the SBP response, suggesting that low E2 receptivity of male hepatocytes is not the only reason for the slow SBP response to E2.…”

Section: Influence Of Other Factorscontrasting

confidence: 99%

In vivo and in vitro studies on sex steroid binding protein (SBP) regulation in rainbow trout (oncorhynchus mykiss): Influence of sex steroid hormones and of factors linked to growth and metabolism

Foucher

Niu

Mourot

et al. 1991

The Journal of Steroid Biochemistry and Molecular Biology

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Summary--The respective roles of sex steroids and hormones related to growth and metabolism, on SBP regulation have been studied in rainbow trout. In vivo, oestradiol (E2) supplementation induces a slow but significant increase of plasma SBP concentration. Testosterone or cortisol injections have no effect. In vitro, the steroid binding protein that accumulates in incubation medium of hepatic cell primary cultures has been characterized and found to be similar to blood SBP. Its production is increased by addition of E2 (maximum: + 300%). This effect develops slowly over several days of culture and is dose dependent; as little as 1-10 nM E2 is effective.Recombinant rainbow trout GH (rtGH)--4).01 to 1 #g/ml--also increases SBP accumulation as compared to control cells and seems to maintain SBP production over culture duration. In preliminary experiments, (1) insulin-like growth factor (IGF) and SBP concentrations were found to change inversely after a 4 days stimulation with increasing concentrations of GH; (2) recombinant human IGF~ (250 ng/ml) tended to be inhibitory when SBP production was expressed per mg of total cellular protein, and a micromolar concentration of bovine insulin was clearly inhibitory.

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Section: Influence Of Other Factorscontrasting

confidence: 99%

In vivo and in vitro studies on sex steroid binding protein (SBP) regulation in rainbow trout (oncorhynchus mykiss): Influence of sex steroid hormones and of factors linked to growth and metabolism

Foucher

Niu

Mourot

et al. 1991

The Journal of Steroid Biochemistry and Molecular Biology

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“…In oviparous animals, the synthesis of VTG by hepatocytes represent a good system with which to study the mechanism of action of steroid hormones [31][32][33][34]. Most of these studies have used hepatocytes of either amphibians (especially Xenopus laevis) or birds (especially chickens), though some have been based on hepatocytes from fish [24,[35][36][37]. Various techniques have been used to culture fish hepatocytes [35,37].…”

Section: Resultsmentioning

confidence: 99%

Vitellogenin synthesis in cultured hepatocytes; an in vitro test for the estrogenic potency of chemicals

Pelissero

Flouriot

Foucher

et al. 1993

The Journal of Steroid Biochemistry and Molecular Biology

266

108

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Smnmary--We describe here an/n vitro technique to assess the estrogenic activity of chemicals. This technique is based on rainbow trout hepatocytes incubated in a basic medium free of any additional growth factors or estrogenic chemicals and uses the production of vitellogenin (VTG) as a marker for the estrogenic potency of the compounds tested. The system allows at least some of the metabolic transformations which are undertaken by the liver cells/n vivo and could therefore be used for xenobiotic compounds which exhibit estrogenic activities after liver metabolic transformation. A dose-response curve was always consistently obtained using estradiol-17fl (E2), with a mid point at around 100 nME 2 and a maximum response at around 1000nM. Established estrogens such as 17al ethynylestradiol (EE2) or diethylstilboestrol (DES) were also tested. EE 2 appeared to be equipotent with E2 and DES slightly less potent. E2 conjugates were, perhaps surprisingly, also very potent. Estradiol-3-sulfate was equipotent with E2 and estradiol-17fl-glucuronide approx. 10% as potent. Other steroids such as androgens and progesterone, though active in the bioassay, were 3 orders of magnitude less potent than E 2. Of the various steroids tested, only cortisol, at concentrations up to 50 #M, was completely inactive. Six different phytoestrogens were tested in the assay. All were weakly estrogenic, possessing approximately one thousanth the potency of E 2 (they were as potent as the androgens and progesterone). All six phytoestrogens, as well as the androgens and progesterone, were tested in the presence of tamoxifen. In all cases tamoxifen reduced the production of VTG significantly, demonstrating that the estrogenic action of all of these compounds was most likely mediated by the E 2 receptor. The potencies determined here may not reflect the situation/n vivo but can provide complementary results about the activity of chemicals which need an hepatic metabolization to be estrogenic. Hepatocyte cultures would profitably be developed in other species to sustain these results.

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“…One might argue that the level of transcriptional induction driven by rtER S is too weak to account for the dramatic induction of rtvtg genes [43]. However, given that rainbow trout VTGs are encoded by ~20 (almost) identical genes, even a modest induction could be amplified by the large number of rtvtg genes.…”

Section: Functional Impact Of Ere Cs and Rtvtgere: The Driving Force mentioning

confidence: 99%

Control of vitellogenin genes expression by sequences derived from transposable elements in rainbow trout

Bouter

Buisine

Grand

et al. 2010

Biochimica et Biophysica Acta (BBA) - Gene Regulatory Mechanism

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In most of oviparous animals, vitellogenins (VTG) are the major egg yolk precursors. They are produced in the liver under the control of estrogens. In rainbow trout (Oncorhynchus mykiss), the vtg genes cluster contains an unusually large number of almost identical gene copies. In order to identify the regulatory elements in their promoters, we used a combination of reporter plasmids containing genomic sequences including putative estrogen response elements (EREs) and we performed transient transfection assays in MCF-7 and yeast cells.We found a functional ERE corresponding to the sequence GGGGCAnnnTAACCT (rtvtgERE), which differs from the consensus ERE (ERE cs ) by three base pairs. This nonpalindromic ERE is located in the env gene of a retrotransposon relic, 180 base pairs upstream of the transcriptional start site. Fluorescence anisotropy experiments confirmed that the purified human estrogen receptor α (hERα) can specifically bind to rtvtgERE. Furthermore, we observe that the stability of hERα-ERE cs and hERα-rtvtgERE complexes is similar with equilibrium dissociation constants of 3.0 nM and 6.2nM respectively, under our experimental conditions. Additionally, this rtvtgERE sequence displays a high E2-responsiveness through ER activation in cellulo.In the rainbow trout, the functional ERE (rtvtgERE) lies within promoter sequences which are mostly composed of sequences derived from transposable elements (TEs), which therefore may have acted as an evolutionary buffer to secure the proper expression of these genes.4

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Vitellogenin gene expression in primary culture of male rainbow trout hepatocytes

Cited by 74 publications

References 21 publications

In vivo and in vitro studies on sex steroid binding protein (SBP) regulation in rainbow trout (oncorhynchus mykiss): Influence of sex steroid hormones and of factors linked to growth and metabolism

In vivo and in vitro studies on sex steroid binding protein (SBP) regulation in rainbow trout (oncorhynchus mykiss): Influence of sex steroid hormones and of factors linked to growth and metabolism

Vitellogenin synthesis in cultured hepatocytes; an in vitro test for the estrogenic potency of chemicals

Control of vitellogenin genes expression by sequences derived from transposable elements in rainbow trout

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