COLLABORATIVE RESEARCH: A Model System for the Development of Behavior

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，还与围产期性腺分泌的类固醇激素有关。虽然已知睾丸雄激素在围产期发育中起重要作用，但雄激素在特定脑细胞内代谢为雌激素。确定雄激素或其雌激素代谢物是分化激素是很复杂的，因为哺乳动物胎盘胎儿的系统实际上“保护”他们不受母体雌激素的影响。因此，让雌激素进入胎儿体内，并量化作用于胎儿的雌激素的量是极其重要的，但几乎不可能实现。费登博士开发了一种有袋动物模型来研究雌激素的作用。新生儿出生时的发育阶段相当于13天的胎鼠或8周的人类胚胎。因为新生的有袋动物本质上是一个外部胎儿，利用有袋动物进行的研究可以提供关于激素对生殖发育影响的独特信息。Fadem博士将调节新生儿的激素环境，然后评估其对成年后行为、形态和生理的影响。这些研究的结果将有助于更好地了解由于发育过程中类固醇激素暴露不足或过量而导致的各种人类出生障碍。

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.