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Phthalates impair germ cell number in the mouse fetal testis by an androgen- and estrogen-independent mechanism.

Lehraiki A, Racine C, Krust A, Habert R, Levacher C - Toxicol. Sci. (2009)

Bottom Line: Conversely, the strong deleterious effects of phthalates on germ cells were constantly present during the active phases of gonocyte development and thus share no relationship with the steroidogenic status.Moreover, all the effects of phthalates were unchanged in testes from mice deficient for estrogen (ERalphaKO or ERbetaKO) or androgen (Tfm) receptors.In conclusion, our results demonstrate that phthalates impair mouse fetal germ cell number similarly to other mammalian species, but are neither estrogenic nor antiandrogenic molecules because their effects do not involve, directly or indirectly, ER or AR.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Gonad Differentiation and Radiobiology, Stem Cells and Radiation Service, Institute of Cellular and Molecular Radiation Biology, Life Sciences Division, Commissariat à l'Energie Atomique, BP 6, 92265 Fontenay-aux-Roses, France.

ABSTRACT
Data from experiments conducted almost exclusively in the rat have established that some phthalates have deleterious effects on the fetal testis probably due to their antiandrogenic and/or estrogenic effects, but their mechanisms of action remain unknown. A recent study reported that phthalates also have deleterious effects on human fetal testis with germ cell number, but not steroidogenesis altered. Therefore, we used organ culture of fetal testes at different stages of development to analyze the direct effects of phthalates on both steroidogenesis and gonocyte development and to determine if the effects of MEHP on these functions reported in the rat can be extended to other mammalian species. We defined specific periods of sensitivity of the fetal mouse testis to MEHP for these two functions and showed that the effects of phthalates on steroidogenesis vary with the developmental stage. Conversely, the strong deleterious effects of phthalates on germ cells were constantly present during the active phases of gonocyte development and thus share no relationship with the steroidogenic status. Moreover, all the effects of phthalates were unchanged in testes from mice deficient for estrogen (ERalphaKO or ERbetaKO) or androgen (Tfm) receptors. In conclusion, our results demonstrate that phthalates impair mouse fetal germ cell number similarly to other mammalian species, but are neither estrogenic nor antiandrogenic molecules because their effects do not involve, directly or indirectly, ER or AR.

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Related in: MedlinePlus

Quantitative real-time PCR analysis of the effect of MEHP (200μM) on mRNA levels of a selected set of genes involved in Leydig cell cholesterol metabolism and steroidogenesis, of LH-R (Lhcgr) and Insl3 genes in E13.5 (white bars) and E18.5 (black bars) testes after 3 days of culture in the absence (A) or presence (B) of 100 ng/ml oLH. The results were calculated by the delta-delta Ct method using an external standard (luciferase) added during RNA extraction as an endogenous reference. The levels of mRNA are expressed as mean of relative unit ± SEM of six to nine cultures with the control animals having a value of 1, with each sample processed in duplicate. *p < 0.05, **p < 0.01, ***p < 0.001 versus corresponding control value in the paired Student's t-test.
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fig4: Quantitative real-time PCR analysis of the effect of MEHP (200μM) on mRNA levels of a selected set of genes involved in Leydig cell cholesterol metabolism and steroidogenesis, of LH-R (Lhcgr) and Insl3 genes in E13.5 (white bars) and E18.5 (black bars) testes after 3 days of culture in the absence (A) or presence (B) of 100 ng/ml oLH. The results were calculated by the delta-delta Ct method using an external standard (luciferase) added during RNA extraction as an endogenous reference. The levels of mRNA are expressed as mean of relative unit ± SEM of six to nine cultures with the control animals having a value of 1, with each sample processed in duplicate. *p < 0.05, **p < 0.01, ***p < 0.001 versus corresponding control value in the paired Student's t-test.

Mentions: Because MEHP had no effect on Leydig cell number, we hypothesized that its effect on steroidogenesis was due to the modulation of the expression of genes coding for proteins involved in cholesterol and testosterone biosynthesis or metabolism. Therefore, mRNA expression of key genes was analyzed by real-time PCR (Fig. 4).


Phthalates impair germ cell number in the mouse fetal testis by an androgen- and estrogen-independent mechanism.

Lehraiki A, Racine C, Krust A, Habert R, Levacher C - Toxicol. Sci. (2009)

Quantitative real-time PCR analysis of the effect of MEHP (200μM) on mRNA levels of a selected set of genes involved in Leydig cell cholesterol metabolism and steroidogenesis, of LH-R (Lhcgr) and Insl3 genes in E13.5 (white bars) and E18.5 (black bars) testes after 3 days of culture in the absence (A) or presence (B) of 100 ng/ml oLH. The results were calculated by the delta-delta Ct method using an external standard (luciferase) added during RNA extraction as an endogenous reference. The levels of mRNA are expressed as mean of relative unit ± SEM of six to nine cultures with the control animals having a value of 1, with each sample processed in duplicate. *p < 0.05, **p < 0.01, ***p < 0.001 versus corresponding control value in the paired Student's t-test.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2742583&req=5

fig4: Quantitative real-time PCR analysis of the effect of MEHP (200μM) on mRNA levels of a selected set of genes involved in Leydig cell cholesterol metabolism and steroidogenesis, of LH-R (Lhcgr) and Insl3 genes in E13.5 (white bars) and E18.5 (black bars) testes after 3 days of culture in the absence (A) or presence (B) of 100 ng/ml oLH. The results were calculated by the delta-delta Ct method using an external standard (luciferase) added during RNA extraction as an endogenous reference. The levels of mRNA are expressed as mean of relative unit ± SEM of six to nine cultures with the control animals having a value of 1, with each sample processed in duplicate. *p < 0.05, **p < 0.01, ***p < 0.001 versus corresponding control value in the paired Student's t-test.
Mentions: Because MEHP had no effect on Leydig cell number, we hypothesized that its effect on steroidogenesis was due to the modulation of the expression of genes coding for proteins involved in cholesterol and testosterone biosynthesis or metabolism. Therefore, mRNA expression of key genes was analyzed by real-time PCR (Fig. 4).

Bottom Line: Conversely, the strong deleterious effects of phthalates on germ cells were constantly present during the active phases of gonocyte development and thus share no relationship with the steroidogenic status.Moreover, all the effects of phthalates were unchanged in testes from mice deficient for estrogen (ERalphaKO or ERbetaKO) or androgen (Tfm) receptors.In conclusion, our results demonstrate that phthalates impair mouse fetal germ cell number similarly to other mammalian species, but are neither estrogenic nor antiandrogenic molecules because their effects do not involve, directly or indirectly, ER or AR.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Gonad Differentiation and Radiobiology, Stem Cells and Radiation Service, Institute of Cellular and Molecular Radiation Biology, Life Sciences Division, Commissariat à l'Energie Atomique, BP 6, 92265 Fontenay-aux-Roses, France.

ABSTRACT
Data from experiments conducted almost exclusively in the rat have established that some phthalates have deleterious effects on the fetal testis probably due to their antiandrogenic and/or estrogenic effects, but their mechanisms of action remain unknown. A recent study reported that phthalates also have deleterious effects on human fetal testis with germ cell number, but not steroidogenesis altered. Therefore, we used organ culture of fetal testes at different stages of development to analyze the direct effects of phthalates on both steroidogenesis and gonocyte development and to determine if the effects of MEHP on these functions reported in the rat can be extended to other mammalian species. We defined specific periods of sensitivity of the fetal mouse testis to MEHP for these two functions and showed that the effects of phthalates on steroidogenesis vary with the developmental stage. Conversely, the strong deleterious effects of phthalates on germ cells were constantly present during the active phases of gonocyte development and thus share no relationship with the steroidogenic status. Moreover, all the effects of phthalates were unchanged in testes from mice deficient for estrogen (ERalphaKO or ERbetaKO) or androgen (Tfm) receptors. In conclusion, our results demonstrate that phthalates impair mouse fetal germ cell number similarly to other mammalian species, but are neither estrogenic nor antiandrogenic molecules because their effects do not involve, directly or indirectly, ER or AR.

Show MeSH
Related in: MedlinePlus