Embryonic exposure to the fungicide vinclozolin causes virilization of females and alteration of progesterone receptor expression in vivo: an experimental study in mice

Abstract

BackgroundVinclozolin is a fungicide that has been reported to have anti-androgenic effects in rats. We have found that in utero exposure to natural or synthetic progesterones can induce hypospadias in mice, and that the synthetic progesterone medroxyprogesterone acetate (MPA) feminizes male and virilizes female genital tubercles. In the current work, we selected a relatively low dose of vinclozolin to examine its in utero effects on the development of the genital tubercle, both at the morphological and molecular levels.MethodsWe gave pregnant dams vinclozolin by oral gavage from gestational days 13 through 17. We assessed the fetal genital tubercles from exposed fetuses at E19 to determine location of the urethral opening. After determination of gonadal sex, either genital tubercles were harvested for mRNA quantitation, or urethras were injected with a plastic resin for casting. We analyzed quantified mRNA levels between treated and untreated animals for mRNA levels of estrogen receptors α and β, progesterone receptor, and androgen receptor using nonparametric tests or ANOVA. To determine effects on urethral length (males have long urethras compared to females), we measured the lengths of the casts and performed ANOVA analysis on these data.ResultsOur morphological results indicated that vinclozolin has morphological effects similar to those of MPA, feminizing males (hypospadias) and masculinizing females (longer urethras). Because these results reflected our MPA results, we investigated the effects of in utero vinclozolin exposure on the mRNA expression levels of androgen, estrogen α and β, and progesterone receptors. At the molecular level, vinclozolin down-regulated estrogen receptor α mRNA in females and up-regulated progesterone receptor mRNA. Vinclozolin-exposed males exhibited up-regulated estrogen receptor α and progesterone receptor mRNA, effects we have also seen with exposure to the synthetic estrogen, ethinyl estradiol.ConclusionThe results suggest that vinclozolin virilizes females and directly or indirectly affects progesterone receptor expression. It also affects estrogen receptor expression in a sex-based manner. We found no in vivo effect of vinclozolin on androgen receptor expression. We propose that vinclozolin, which has been designated an anti-androgen, may also exert its effects by involving additional steroid-signaling pathways.

In Utero and Lactational Exposure to Low-Dose Genistein-Vinclozolin Mixture Affects the Development and Growth Factor mRNA Expression of the Submandibular Salivary Gland in Immature Female Rats

“…Nevertheless, early exposure to vinclozolin led to some female virilization, as shown by AGD at PND21, suggesting a predominantly androgenic effect, which was previously reported for the female reproductive tract (Buckley et al 2006). This apparent discrepancy could be the result of the androgen agonist activities of the M2 vinclozolin metabolites (Molina-Molina et al 2006;Wong et al 1995), since a complementary study indicated that M2 metabolite, but not vinclozolin, was recovered in the plasma and milk of lactating mothers (Auger et al 2010).…”

Developmental exposure to environmental endocrine disruptors: Consequences within the ovary and on female reproductive function☆

“…Further analysis of the in utero effects of vinclozolin revealed that male embryos underwent feminization and female embryos became masculinized when dams were given vinclozolin. As suggested by the data, the morphogenic actions of vinclozolin within embryos could be a result of the effects of this compound on the expression of AR, ER, and/ or progesterone receptors [136].ii. DDE-Another compound possessing anti-androgen activity is the DDT metabolite 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) [137].…”

Specific transgenerational imprinting effects of the endocrine disruptor methoxychlor on male gametes

“…Vinclozolin (VCZ), a fungicide possessing an anti-androgenic activity affected spermatogenesis inducing decreases in sperm number and motility and an increase in apoptosis in the seminiferous tubules germ cells (Shimamura et al 2002, Anway et al 2005, Buckley et al 2006, Elzeinova et al 2008. MXC, administered perinatally or during gestation, was also found to affect spermatogenesis in the adult or in the offspring respectively (Chapin et al 1997, Anway et al 2005).…”