Expression of SRC-1 and p/CIP in the Mouse Testis

Abstract

The function of the testis is regulated by androgens. The activity of testicular androgens is expressed through androgen receptors and many kinds of coactivators in a similar way as with other steroid hormones. In this study, the expression of androgen receptors (AR), the steroid receptor coactivator-1 (SRC-1), and the p300/CBP/co-integrator protein (p/CIP) in the mouse testis was analyzed by immunohistochemistry. The AR signals were detected in the nucleus of peritubular contractile cells, interstitial cells and Sertoli cells. The AR signals localized in the nuclei of Sertoli cells changed according to the spermatogenic cycle of the seminiferous epithelium. In contrast, the p/CIP showed a strong signals in Sertoli cells at all stages of the spermatogenic cycle in adult mice. SRC-1 was detected in nuclei of Sertoli cells during the premature stage of testis, followed by gradual decrease and no signal was demonstrated in that of adult testis. This suggests that SRC-1 does not contribute to androgen action in the mature testis but does so during the premature stage. Since the expression of p/CIP was observed in a wider range than that of AR, p/CIP supported the function of AR in the testes after maturation. There are various types of coactivators of AR in testis that may play different roles.