Subfertility in androgen-insensitive female mice is rescued by transgenic FSH K. A. Walters A,B , M. C. Edwards A , M. Jimenez A , D. J. Handelsman A and C. M. Allan A A ANZAC Research Institute, Andrology Laboratory, University of Sydney, Concord Hospital, Hospital Road, Concord, NSW 2139, Australia. B Corresponding author. Email: k.walters@unsw.edu.au Abstract. Androgens synergise with FSH in female reproduction but the nature of their interaction in ovarian function and fertility is not clear. In the present study, we investigated this interaction, notably whether higher endogenous FSH can overcome defective androgen actions in androgen receptor (AR)-knockout (ARKO) mice. We generated and investigated the reproductive function of mutant mice exhibiting AR resistance with or without expression of human transgenic FSH (Tg-FSH). On the background of inactivated AR signalling, which alone resulted in irregular oestrous cycles and reduced pups per litter, ovulation rates and antral follicle health, Tg-FSH expression restored follicle health, ovulation rates and litter size to wild-type levels. However, Tg-FSH was only able to partially rectify the abnormal oestrous cycles observed in ARKO females. Hence, elevated endogenous FSH rescued the intraovarian defects, and partially rescued the extraovarian defects due to androgen insensitivity. In addition, the observed increase in litter size in Tg-FSH females was not observed in the presence of AR signalling inactivation. In summary, the findings of the present study reveal that FSH can rescue impaired female fertility and ovarian function due to androgen insensitivity in female ARKO mice by maintaining follicle health and ovulation rates, and thereby optimal female fertility. Additional keywords: androgen receptor, female fertility, ovarian function. Received 12 January 2016, accepted 30 May 2016, published online 22 June 2016 Introduction Androgens play a key role in female fertility because testos- terone is an obligatory precursor for aromatisation into oestra- diol, the canonical female sex steroid that is critical to female reproductive function (Hillier et al. 1994). In addition, direct androgen receptor (AR)-mediated actions of androgen are essential to optimise ovarian function and fertility (Walters 2015). The AR is expressed throughout the hypothalamic– pituitary–gonadal axis and is evolutionarily conserved. Within the ovary, the AR is expressed at most stages of follicular development, most prominently in granulosa cells (Walters et al. 2008). Using global and cell-specific AR-knockout (ARKO) female mice, we and others have proven a direct involvement of ARs in the regulation of female reproductive function (Hu et al. 2004; Shiina et al. 2006; Walters et al. 2007, 2012; Sen and Hammes 2010). Global ARKO females are sub- fertile and exhibit irregular oestrous cycles, an impaired ovulatory LH surge, abnormal follicular development, fewer preovulatory follicles and corpora lutea (CL) and more atretic follicles (Hu et al. 2004; Shiina et al. 2006; Walters et al. 2007; Cheng et al. 2013). Findings from analysis of granulosa cell-specific ARKO (GCARKO) female mice has identified that granulosa cells are a key site for AR-mediated actions involved in optimising female fertility, by maintaining normal follicle development (Sen and Hammes 2010; Walters et al. 2012). Furthermore, an extraovarian (neuroendocrine) role for AR-mediated actions in maintaining female fertility was proven by the findings that transplantation of wild-type control mouse ovaries into ovariectomised ARKO female mice led to irregular oestrous cycles and reduced fertility, whereas cross-transplantation of control or ARKO ovaries into ovariectomised wild-type control hosts had no effect on oestrous cycles or fertility (Walters et al. 2009). In addition, pituitary- specific ARKO (PitARKO) female mice are subfertile and exhibit reduced ovulatory FSH and LH levels, together with impaired follicle health and ovulation (Wu et al. 2014). FSH secreted by pituitary gonadotrophs in a cyclic manner, driven by patterned hypothalamic gonadotrophin-releasing hormone (GnRH) secretion and related neuroendocrine feed- back mechanisms, plays a major role in the recruitment and development of healthy ovarian follicles through to the preovu- latory stage (McGee and Hsueh 2000). FSH and its receptor (FSHR) are necessary for normal follicle development because CSIRO PUBLISHING Reproduction, Fertility and Development, 2017, 29, 1426–1434 http://dx.doi.org/10.1071/RD16022 Journal compilation Ó CSIRO 2017 www.publish.csiro.au/journals/rfd