Lonstein Joseph S, Rood Benjamin D, De Vries Geert J
Center for Neuroendocrine Studies, University of Massachusetts, Tobin Hall, Amherst, Massachusetts 01003, USA.
Horm Behav. 2002 Feb;41(1):80-7. doi: 10.1006/hbeh.2001.1740.
We previously found a large sex difference in the parental responsiveness of adult virgin prairie voles (Microtus ochrogaster) such that most males are spontaneously parental, whereas most females are not. Because this sex difference is independent of the gonadal hormones normally circulating in adult virgin voles, the present study examined whether perinatal hormones influence the development of this sex difference. Males were treated prenatally (via their pregnant dam) with both the androgen receptor blocker flutamide (5 mg/day/dam) and the aromatase inhibitor ATD (1 mg/day/dam), or oil, for the last 2 weeks of gestation. Half of the subjects from each group were castrated on the day of birth and the other half received a sham surgery. As adults, intact males were castrated and all males received a silastic capsule filled with testosterone. Prenatal treatment with flutamide and ATD had no effect on males' behavior toward pups, but neonatal castration significantly reduced the percentage of males acting parentally. In a second experiment, females were exposed to testosterone propionate (TP; 50 microg/day/dam) or oil via their dam during the last 2 weeks of gestation. For the first neonatal week, half of the females from each group were injected with TP (1 mg/day) and the other half oil. As adults, females were ovariectomized and half from each group received a testosterone-filled capsule and the other half received an empty capsule. None of the perinatal TP treatments increased females' parental responsiveness, although females from all groups that received testosterone capsules as adults were highly parental. Therefore, although postnatal testicular hormones are necessary for high parental responsiveness in males, the behavior of females is not influenced by perinatal exposure to testosterone.
我们之前发现成年未交配的草原田鼠（Microtus ochrogaster）在亲代反应性上存在很大的性别差异，即大多数雄性会自发地表现出亲代行为，而大多数雌性则不会。由于这种性别差异独立于成年未交配田鼠体内正常循环的性腺激素，因此本研究探讨了围产期激素是否会影响这种性别差异的发育。在妊娠的最后两周，雄性通过其怀孕的母鼠接受雄激素受体阻滞剂氟他胺（5毫克/天/母鼠）和芳香化酶抑制剂ATD（1毫克/天/母鼠）或油的产前处理。每组一半的受试者在出生当天进行去势手术，另一半接受假手术。成年后，完整的雄性被去势，所有雄性都接受了一个填充有睾酮的硅橡胶胶囊。产前用氟他胺和ATD处理对雄性对幼崽的行为没有影响，但新生期去势显著降低了表现出亲代行为的雄性的比例。在第二个实验中，雌性在妊娠的最后两周通过其母鼠接触丙酸睾酮（TP；50微克/天/母鼠）或油。在新生期的第一周，每组一半的雌性注射TP（1毫克/天），另一半注射油。成年后，雌性进行卵巢切除，每组一半接受填充有睾酮的胶囊，另一半接受空胶囊。尽管所有成年后接受睾酮胶囊的组中的雌性都表现出高度的亲代行为，但围产期的TP处理均未增加雌性的亲代反应性。因此，尽管产后睾丸激素对于雄性的高亲代反应性是必要的，但雌性的行为不受围产期接触睾酮的影响。
