This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The overall goal of our research is to understand the relationship between increasing obesity and decreasing fertility in humans and other mammals using the lethal yellow mouse model. We are currently working on the role of the hormone leptin in ovarian function and oocyte development and the adverse effects of leptin resistance on follicle development, oocyte maturation, and embryo viability.