Expression of dihydrotestosterone synthases and androgen receptor in sheep oviduct ampulla and its regulation by estradiol and progesterone

Abstract

Oviduct ampulla plays an important role in steroid hormone-regulated sperm-oocyte binding in female animals. Although studies have shown that androgen receptor are expressed in many species oviduct, the interaction among androgen receptor (AR), estradiol (E2) and progesterone (P4) in the sheep oviduct have rarely been reported. In this study, we evaluated the localization of two isoforms of dihydrotestosterone (DHT) sythetase enzymes 5α-reductase (5α‐red1, 5α‐red2) and AR in sheep oviduct ampulla by immunohistochemistry and immunofluorescence. Results showed that they were all distributed in oviduct epithelium layer. In epithelial cells, 5α‐red1, 5α‐red2 were expressed in cytoplast and nuclear, but AR were stained in nuclear. We also investigated their expression pattern in the sheep oviduct ampulla at different development stages of follicles (Large follicles stage; hemorrhagium, luteum and albicans of corpus stage) by molecular experiments. We found that 5α‐red1, 5α‐red2 and AR mRNA abundance and protein were expressed highest in corpus albicans stage and lowest in corpus hemorrhagium stage. In vitro, when sheep oviduct ampulla epithelial cells (SOAECs) were cultured and treated with different concentrations of E2/P4 (10−9–10−6 M), we found that E2 inhibited the expression of AR mRNA and protein, while P4 promoted this expression. In addition, when the SOAECs were treated with E2 (10−8 M) and/or its non-selective inhibitor ICI182780 (10−7 M) as well as with P4 (10−6 M) and/or its non-specific inhibitor RU486 (10−5 M), we found that E2 and P4 inhibited and promoted the expression of AR mRNA and proteins, respectively, via their nuclear receptor pathways. This study provides a basic insight for the further research of oviduct epithelium physiological function closely related to androgen.