PROJECT SUMMARY Anti-Müllerian hormone (AMH) plays a key role during ovarian follicular development. We have advanced our understanding of the dynamic expression, direct action, and physiological role of AMH during folliculogenesis in rhesus macaques since the initial award of the project. Data suggest that AMH is produced heterogeneously by developing follicles and exhibits stage-dependent regulatory effects by promoting preantral follicle growth and preventing antral follicle maturation. Stage-specific AMH modulation improves follicle growth and maturation in vitro to generate competent oocytes. Therefore, further research is warranted to elucidate the downstream molecular and cellular events regulated by AMH at the specific stages of follicular development, as well as the potential for modulation of AMH actions to improve ovarian function and female fertility. Our preliminary studies show that (a) AMH administration in vivo promotes preantral follicle growth, resulting in the increased number of antral follicles in the ovary; (b) primordial follicle activation and growth to the preantral stage is achieved by ovarian tissue culture after cryopreservation; and (c) preantral follicles are maintained in a state of physiological hypoxia. AMH has the potential to regulate cell cycle progression by limiting actions of hypoxia-inducible factor, and to control cellular energy production by inducing creatine biosynthesis and metabolism under hypoxia. Thus, studies will be performed to test the hypothesis that stage- specific modulation of AMH actions facilitates follicular development in vivo and in vitro, which in turn improves fertility outcomes. Aim 1 will evaluate the impact of AMH priming on ovarian response to gonadotropin stimulation during IVF (in vitro fertilization). AMH will be administered in vivo in macaques at advanced reproductive age or with poor response to controlled ovarian stimulation (COS). The COS protocol will then be performed to evaluate IVF efficacy. Aim 2 will examine the effect of AMH modulation on in vitro maturation of follicles from cryopreserved macaque and human ovarian tissue. Vitrified-warmed ovarian cortex will be cultured to induce primordial follicle activation and growth to the preantral stage. Preantral follicles will then be isolated and cultured with AMH modulation for oocyte maturation. Aim 3 will determine the molecular mechanisms whereby AMH regulates cell proliferation and energy production during follicular development. Macaque preantral follicles will be cultured at 5% O2 with AMH supplementation or knockdown. Factors regulating cell cycle progression and creatine biosynthesis/metabolic pathway components will be analyzed. The proposed studies will provide important insight into the mechanism of stage-dependent AMH actions in regulating follicular development and ovarian function using a nonhuman primate model that is an excellent surrogate for understanding reproductive processes in women. The findings ...