Androgens have essential roles in the regulation of follicular development and female fertility. Androgen excess is the leading defect in polycystic ovary syndrome (PCOS) patients and involved in the ovarian dysfunction. The aim of this study was to elucidate the regarding regulatory role of androgen in the follicular development of female mouse. Immunohistochemical staining and Western blot analyses were performed to detect androgen receptor (AR) and Connexin 43 (Cx43) expression in ovaries from both control and testosterone-treated group mice. In this study, localizations of AR and Cx43 were dramatically altered in testosterone-treated mouse ovaries. In addition, AR expression was significantly increased, whereas Cx43 expression was markedly decreased after testosterone treatment. Alterations of AR and Cx43 expression by testosterone with concomitant reduction of MII oocytes. Overall, these results suggest the involvement of androgen in the regulation of AR and Cx43 localizations in mouse ovary. Alterations of AR and Cx43 expression by testosterone may affect normal folliculogenesis. Together these findings will enable us to begin understanding the important roles of AR and Cx43 actions in the regulation of follicular development, as well as providing insights into the role of AR and Cx43 actions in the androgen-associated reproductive diseases such as PCOS.