TGFβ (transforming growth factor β) superfamily members and their receptors in the fetal porcine ovaries: effect of prenatal flutamide treatment

We have recently demonstrated that antiandrogen treatment during fetal life resulted in delayed folliculogenesis. The aim of the present study was to investigate the effect of androgen deficiency induced by flutamide on the expression of TGFβ superfamily members and their receptors which are involved in follicle formation and its transition to the primary stage. Pregnant gilts were injected with flutamide (for seven days, 50 mg/day/kg b.w.) or corn oil (controls) starting at 43 (GD50), 83 (GD90) or 101 (GD108) gestational day. The expression in fetal ovaries of selected TGFβ superfamily members (AMH, BMP4, GDF9), their receptors (AMHR-II, BMPR-IB, BMPR-II), and Smad1 and Smad3 proteins involved in signal transduction were investigated by real-time PCR and/or immunohistochemistry. Flutamide treatment increased the expression of BMP4 mRNA on GD50 and GD108 and BMPR-IB mRNA on GD50. The expression of BMPR-II was decreased at mRNA level and lower immunostaining intensity was observed after flutamide administration only on GD50. GDF9 and AMHR-II mRNA expression levels were significantly downregulated in both GD90 and GD108 groups. However, AMHR-II was immunolocalized only on GD108 and less positively stained oocytes were found after flutamide treatment. AMH mRNA level was diminished in the GD90 group, while it was elevated in the GD108 group. Moreover, the higher amounts of positively stained oocytes for phosphorylated form of Smad1 were observed following flutamide administration on GD108. Experimentally-induced androgen deficiency during fetal development deregulates the expression level of some of TGFβ superfamily members and their receptors which may affect primordial follicle assembly. Our findings further underline the role of androgens in the early stages of follicle development.