Effects of FSH on testicular mRNA transcript levels in the hypogonadal mouse M H Abel, D Baban, S Lee, H M Charlton and P J O’Shaughnessy1 Department of Physiology, Anatomy and Genetics, University of Oxford, Le Gros Clarke Building, Oxford OX1 3QX, UK 1Institute of Comparative Medicine, University of Glasgow Veterinary School, Bearsden Road, Glasgow G61 1QH, UK (Correspondence should be addressed to P J O’Shaughnessy; Email: p.j.oshaughnessy@vet.gla.ac.uk) (D Baban is now at Genomics Group, The Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK) Abstract FSH acts through the Sertoli cell to ensure normal testicular development and function. To identify transcriptional mechanisms through which FSH acts in the testis, we have treated gonadotrophin-deﬁcient hypogonadal (hpg) mice with recombinant FSH and measured changes in testicular transcript levels using microarrays and real-time PCR 12, 24 and 72 h after the start of treatment. Approximately 400 transcripts were signiﬁcantly altered at each time point by FSH treatment. At 12 h, there was a clear increase in the levels of a number of known Sertoli cell transcripts (e.g. Fabp5, Lgals1, Tesc, Scara5, Aqp5). Additionally, levels of Leydig cell transcripts were also markedly increased (e.g. Ren1, Cyp17a1, Akr1b7, Star, Nr4a1). This was associated with a small but signiﬁcant rise in testosterone at 24 and 72 h. At 24 h, androgen-dependent Sertoli cell transcripts were up-regulated (e.g. Rhox5, Drd4, Spinlw1, Tubb3 and Tsx) and this trend continued up to 72 h. By contrast with the somatic cells, only ﬁve germ cell transcripts (Dkkl1, Hdc, Pou5f1, Zfp541 and 1700021K02Rik) were altered by FSH within the time-course of the experiment. Analysis of canonical pathways showed that FSH induced a general decline in transcripts related to formation and regulation of tight junctions. Results show that FSH acts directly and indirectly to induce rapid changes in Sertoli cell and Leydig cell transcript levels in the hpg mouse but that effects on germ cell development must occur over a longer time-span. Journal of Molecular Endocrinology (2009) 42, 291–303 Introduction Postnatal testicular growth, spermatogenesis and fertility are dependent upon the pituitary gonado- trophins FSH and LH. LH acts directly on Leydig cells to stimulate androgen production, while androgens and FSH stimulate spermatogenesis through direct action on the Sertoli cells (McLachlan et al. 2002). The role of gonadotrophins is clearly seen in the hypogo- nadal (hpg) mouse that lacks GnRH (Mason et al. 1986) and, consequently, has undetectable circulating levels of LH and FSH (Cattanach et al. 1977). The gonads of the hpg mouse remain in a pre-pubertal state throughout life, with spermatogenesis blocked at early meiosis (Cattanach et al. 1977, Myers et al. 2005) although treatment with exogenous gonado- trophins or androgens will increase testicular growth and restore germ cell development (Charlton et al. 1983, Singh & Handelsman 1996a,b, Haywood et al. 2003). In recent years, generation of mice lacking individual hormones or hormone receptors has allowed us to investigate more clearly the roles played by LH, FSH and androgen in the regulation of testicular function. In particular, study of mice lacking androgen receptors (AR) in the Sertoli cells (SCARKO (De Gendt et al. 2004)) has shown that androgens are essential for spermatocyte progression through meio- sis. By contrast, mice lacking FSH (FSHbKO (Kumar et al. 1997)) or the FSH receptor (FSHRKO; Dierich et al. 1998, Abel et al. 2000) are fertile with all stages of spermatogenesis present. Nevertheless, in FSHRKO and FSHbKO mice there is a reduction in sperm number and quality (Krishnamurthy et al. 2001, Wreford et al. 2001) suggesting that FSH action optimises spermatogenesis. In addition, comparison of SCARKO mice with mice lacking both FSHR and AR on the Sertoli cells has shown that FSH acts to increase Sertoli cell number, total germ cell number and the number of germ cells associated with each Sertoli cell (Abel et al. 2008). This is achieved by an increase in the number of spermatogonia and enhanced entry of these cells into meiosis (Abel et al. 2008). Previous studies have identiﬁed a number of Sertoli cell products or mRNA transcripts that are FSH- sensitive including, for example, inhibin, AR, transfer- rin, doublesex and mab-3 related transcription factor1 (DMRT), androgen-binding protein and inducible cAMP early repressor (Morris et al. 1988, Verhoeven & Cailleau 1988, Skinner et al. 1989, Monaco et al. 1995, Chen & Heckert 2001). In addition, an earlier study has Journal of Molecular Endocrinology (2009) 42, 291–303 DOI: 10.1677/JME-08-0107 0952–5041/09/042–291 q 2009 Society for Endocrinology Printed in Great Britain Online version via http://www.endocrinology-journals.org This is an Open Access article distributed under the terms of the Society for Endocrinology’s Re-use Licence which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 291