A long-term focus in our laboratory is mammalian fertilization and the molecules involved in the fertilization process. Research is centered on interactions between sperm and oocyte plasma membrane molecules after sperm have undergone the acrosome reaction since our earlier work demonstrated that this was frequently the limiting step in vivo in subfertile animals. Details of these interactions including receptor/ligand pairings are still largely unknown. Environmental stresses such as elevated ambient temperature affect both the sperm’s ability and the oocyte’s ability to interact with each other at the plasma membrane level. We hypothesize that this is due to decreased/defective synthesis of interacting molecules. 

A second focus in our laboratory is the regulation of Sertoli cell proliferation. Sertoli cell numbers are a major determinant of postpuberal testis size and sperm production. The number of Sertoli cells is generally believed to be determined prepuberally. We have found that reducing endogenous estrogen in the boars postnatally leads to increased proliferation of Sertoli cells and larger postpuberal testes in the pig. This occurs without altered pituitary hormones in boars and strongly suggests a locally mediated mechanism. 

The pig is the primary species studied due in part to its importance to US and world food production as well as the availability of large numbers of gametes and comparatively short gestation and prepuberal intervals. In vitro oocyte maturation and fertilization, in vitro bioassays, gene expression (qPCR), immunohistochemistry, gel electrophoresis and western blotting, heterospermic insemination and other in vivo animal trials, CRISPR editing and embryo transfer are techniques used to advance our laboratory research goals.