Dr. Mark Estienne (Virginia Polytechnic Institute and State University ) "Neuroendocrine Regulation of Reproduction in Male Domestic Animal Species: Role of Excitatory Amino Acids"

Excitatory amino acids such as glutamate and aspartate are the major neurotransmitters in the mammalian central nervous system. Glutamate and aspartate have also been implicated in the neuroendocrine control of anterior pituitary hormone secretion. The discussion will focus on the role of excitatory amino acids in modulating gonadotropin secretion and sexual development in male domestic animal species.

Dr. Larry Johnson (Texas A&M) "Efficiency of Spermatogenesis in Animals and Humans"

Spermatogenesis is divided into three major events (spermatocytogenesis, meiosis, and spermiogenesis) in the production of its major products, male gametes. Spermatogenic stages are superimposed on these major events. Spermatogenesis may be evaluated from the ejaculate or from the testis by estimating sperm production rates and germ cell degeneration rates from numbers of spermatogonia, spermatocytes, or spermatids. Natural alteration in efficiency of spermatogenesis includes pubertal development, season, aging, and species differences. Numbers of Sertoli cells play important roles in efficiency of spermatogenesis in man and beast.

Dr. David Miller (University of Illinois) "Fertilization: A Male's Perspective"

During fertilization, sperm and eggs bind to each other using receptors. Expression of these receptors is shared among several species. In addition to serving as an adhesion molecule, the receptor on sperm that binds the oocyte zona pellucida also triggers the acrosome reaction in sperm, allowing sperm to penetrate through the zona pellucida and fertilize the oocyte. Discussion will focus on current data about the identity of these receptors and their function in several species.

Dr. Frank Bartol (Auburn University) "Novel Events in Uterine Organization and Function"

Mechanisms that are known or hypothesized to be involved in organizational events that support morphogenesis and cytodifferentiation of uterine tissues will be discussed, with particular emphasis given to the endometrium. The potential for organizational disruption and consequences of such disruption on subsequent uterine function and reproductive performance will be addressed.

Dr. George Foxcroft (University of Alberta) "Insights into Conceptus-Reproductive Tract Interactions in the Pig"

In three different experimental paradigms, an early rise in plasma progesterone concentrations in the gilt and sow is associated with higher embryonic survival. We will present data from recent studies exploring 1) patterns of prenatal loss in modern genotypes, 2) associations between differences in progesterone secretion in early pregnancy and oviduct gene expression and secretory activity, and 3) control of gene expression in the developing conceptus and uterine epithelium, which allows for conceptus expansion and attachment/implantation.

Dr. Char Farin (North Carolina State University) "Fetal Development of Manipulated Embryos: Possible Associations with Uterine Function"

In vitro production and manipulation of livestock embryos has been associated with alterations in preimplantation embryonic morphology as well as with alterations in fetal development following transfer into recipient females. This presentation will focus on the types of alterations that have been identified as well as on possible intrinsic (embryonic/fetal) and extrinsic (maternal/ environmental) mechanisms that may be responsible for these effects on development.