Effect of gestational antiandrogen treatment on Dicer1 expression in the porcine fetal gonads

Recently, we have demonstrated that flutamide-induced androgen deficiency during fetal life led to changes in gene expression that affected both testicular functions and follicular formation. It is known that microRNA-mediated genes regulation is essential for gonadal development and function. Thus, the aim of the present study was to examine whether prenatal flutamide exposure influences expression of Dicer1, an enzyme involved in microRNA maturation, in gonads of porcine fetuses during mid- and late gestation. Pregnant gilts were injected with flutamide (50mg/day/kg b.w.) or corn oil (controls) between days 43-49, 83-89 or 101-107 of gestation. The fetal gonads were obtained on gestational day 50 (GD50), 90 (GD90) or 108 (GD108). To assess Dicer1 mRNA expression real-time PCR were performed. Furthermore, immunohistochemical Dicer1 localization was conducted. In testes from flutamide treated fetuses, increased Dicer1 mRNA expression was observed in the GD50 and GD108 groups, but decreased in the GD90 group. Dicer1 was immunolocalized in the fetal Leydig cells in both control and flutamide-treated groups. In fetal ovaries, antiandrogen treatment increased Dicer1 mRNA level in the GD50 and GD90 groups. In control and flutamide-exposed groups, Dicer1 was localized in the germ cells within oogonia/oocyte nests as well as in the granulosa cells and oocytes of forming follicles. Concluding, diminished androgen action during gestation induces changes in Dicer1 mRNA expression, which may affect post-transcriptional gene regulation via miRNAs in porcine fetal gonads. However, it seems that androgens exert diverse biological effects depending on the gestational period.