COLLABORATIVE RESEARCH: A Model System for the Development of Behavior

FADEM 9723043哺乳动物生殖行为的性别差异不仅由基因和成年期产生的激素决定，还由围产期性腺分泌的类固醇激素决定。虽然已知睾丸雄激素在围产期发育中起重要作用，但雄激素是在特定的脑细胞内代谢成雌激素的。确定一种雄激素或它的雌激素代谢物是否是分化激素是很复杂的，因为胎盘哺乳动物的胎儿实际上有保护他们免受母体雌激素伤害的系统。因此，将雌激素注入胎儿，并量化作用于胎儿的雌激素的数量是极其重要的，但几乎不可能实现。法德姆博士开发了一个有袋类动物模型来研究雌激素的作用。这些新生儿出生的发育阶段相当于13天的胎鼠或8周的人类胚胎。因为新生的有袋类动物本质上是一个外部胎儿，利用有袋类动物的研究可以给出关于激素对生殖发育影响的独特信息。法德姆博士将调节新生儿的荷尔蒙环境，然后评估成年后对行为、形态和生理的影响。这些研究的结果将有助于更好地了解各种人类出生障碍，这些疾病是由于发育过程中类固醇激素暴露不足或过多造成的。

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.