Mullerian inhibiting substance (MIS), a member of the TGF-beta family of growth and differentiation factors, has the essential role during male embryonic sexual differentiation of causing involution of the Mullerian ducts, the anlagen of the female internal reproductive tracts. The unexpected phenotypes of Leydig cell hyperplasia and neoplasia in mice with targeted deletions of the genes for MIS or its receptor, however, raised the prospect of a novel role for MIS in the developing testis. These data suggested that MIS has an essential role in helping to maintain a normal complement of Sertoli and Leydig cells in the maturing testis. This proposal will test the hypothesis that MIS prevents the unrestrained proliferation of immature Leydig cells and modulates their responsiveness to mitogenic factors in the maturing testis.
The Specific Aims of this proposal are to: 1.) Characterize the expression of the MIS type II receptor in Sertoli and Leydig cells to verify the ability of MIS to signal in these cells, and examine the anti-proliferative role of MIS in primary Leydig and Sertoli cells to help elucidate the interplay of hormonal influences on the control of cellular proliferation in the developing testis. 2.) Delineate the testicular phenotypes (cell numbers and differentiated function) of MIS transgenic and knockout mice by stereologic studies and in vivo assessment of proliferation, and examine the anti-proliferative activity of MIS in these animal models, and 3.) Investigate the molecular mechanisms by which MIS inhibits Leydig cell proliferation by determining whether MIS causes cell cycle arrest or apoptotic cell death. These studies to elucidate the paracrine and autocrine actions of MIS in developing Leydig and Sertoli cells will advance our understanding of a novel pathway for control of cellular proliferation in the postnatal testis. Inhibitors of proliferation are increasingly being recognized as having critical roles in counter-acting the actions of mitogenic agents to achieve balanced tissue growth and morphogenesis. Thus the anti-proliferative action of MIS on the testicular somatic cells may help control testicular morphogenesis and function; processes that are essential for normal sexual differentiation and attainment of secondary sexual maturation and reproductive fertility. Moreover, clarification of the pathway by which MIS prevents unregulated cellular proliferation and neoplastic transformation of Leydig cells will provide insights into the pathogenesis of testicular tumorigenesis.

National Institute of Health (NIH)
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
Application #
Study Section
Reproductive Biology Study Section (REB)
Program Officer
Freeman, Colette S
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Massachusetts General Hospital
United States
Zip Code
Wu, Xiufeng; Zhang, Ningning; Lee, Mary M (2012) Mullerian inhibiting substance recruits ALK3 to regulate Leydig cell differentiation. Endocrinology 153:4929-37
Wu, Xiufeng; Arumugam, Ramamani; Zhang, Ningning et al. (2010) Androgen profiles during pubertal Leydig cell development in mice. Reproduction 140:113-21
Wu, Xiufeng; Wan, Shengqin; Pujar, Shashikant et al. (2009) A single base pair mutation encoding a premature stop codon in the MIS type II receptor is responsible for canine persistent Müllerian duct syndrome. J Androl 30:46-56
Wu, Xiufeng; Arumugam, Ramamani; Baker, Stephen P et al. (2005) Pubertal and adult Leydig cell function in Mullerian inhibiting substance-deficient mice. Endocrinology 146:589-95
Lee, Mary M; Misra, Madhusmita; Donahoe, Patricia K et al. (2003) MIS/AMH in the assessment of cryptorchidism and intersex conditions. Mol Cell Endocrinol 211:91-8
Misra, Madhusmita; MacLaughlin, David T; Donahoe, Patricia K et al. (2003) The role of Mullerian inhibiting substance in the evaluation of phenotypic female patients with mild degrees of virilization. J Clin Endocrinol Metab 88:787-92
Misra, Madhusmita; MacLaughlin, David T; Donahoe, Patricia K et al. (2002) Measurement of Mullerian inhibiting substance facilitates management of boys with microphallus and cryptorchidism. J Clin Endocrinol Metab 87:3598-602
Sriraman, V; Niu, E; Matias, J R et al. (2001) Mullerian inhibiting substance inhibits testosterone synthesis in adult rats. J Androl 22:750-8
Lee, M M; Seah, C C; Masiakos, P T et al. (1999) Mullerian-inhibiting substance type II receptor expression and function in purified rat Leydig cells. Endocrinology 140:2819-27