Fadem 9723043 Sex differences in reproductive behavior in mammals are determined not only by the genes and by hormones produced in adulthood, but also by steroid hormones secreted by the gonads during perinatal development. Although it is known that testicular androgens play an important role during perinatal development, androgens are metabolized into estrogens within specific brain cells. Determining whether an androgen or its estrogenic metabolite is the differentiating hormone is complicated since placental mammalian fetuses have systems which actually "protect" them from maternal estrogen. Thus, getting estrogen to the fetus and quantifying the amount of estrogen acting on the fetus is extremely important yet almost impossible to achieve. Dr. Fadem has developed a marsupial model to examine the role of estrogen. The newborns are born at a developmental stage equivalent to that of a 13-day fetal rat or 8-week human embryo. Because the newborn marsupial is essentially an external fetus, studies utilizing marsupials can give unique information about the effects of hormones on reproductive development. Dr. Fadem will modulate the hormonal environment of the newborns and then assess the effects on behavior, morphology and physiology in adulthood. The results from these studies will contribute to a better understanding of various human birth disorders that result from insufficient or excess steroid hormone exposure during development.
