Albert D J, Walsh M L
Psychology Department, University of British Columbia Vancouver, Canada.
Physiol Behav. 1995 Jun;57(6):1035-8. doi: 10.1016/0031-9384(94)00337-5.
Female rats were tested for aggression toward an unfamiliar female conspecific 13 days following the beginning of cohabitation with a male. Forty-eight hours later, half of the females that displayed aggression were ovariectomized. To maintain pregnancy, they were also given Silastic implants of estradiol (1-mm tube) and progesterone (6 tubes, 30-mm long; Dow-Corning tubing #602-305) sufficient to maintain pregnancy but at lower levels than those normally present. Control females were given a sham ovariectomy and implanted with empty tubes. Each animal received a second aggression test at 48 h following surgery and a third test, 3 days following the second. Hormone implants successfully maintained pregnancy and supported the normal development of the pups. However, Ovariectomized females with hormone implants did not spontaneously give birth. Ovariectomized females displayed less aggression than their sham-ovariectomized counterparts at the second and third aggression tests. The difference was due to an increasing level of aggression by the control but not the experimental animals. These results are consistent with other evidence that circulating gonadal hormones influence the onset of maternal aggression in the female rat.
雌性大鼠在与雄性同居开始13天后，接受针对陌生雌性同种个体的攻击性测试。48小时后，对表现出攻击性的雌性大鼠中的一半进行卵巢切除。为维持妊娠，还给它们植入了足够维持妊娠但低于正常水平的雌二醇（1毫米管）和孕酮（6根，30毫米长；道康宁管#602 - 305）的硅橡胶植入物。对照雌性大鼠接受假卵巢切除并植入空管。每只动物在手术后48小时接受第二次攻击性测试，并在第二次测试3天后接受第三次测试。激素植入物成功维持了妊娠并支持幼崽的正常发育。然而，植入激素的卵巢切除雌性大鼠并未自然分娩。在第二次和第三次攻击性测试中，植入激素的卵巢切除雌性大鼠的攻击性低于假卵巢切除的对应大鼠。差异是由于对照动物的攻击性水平增加，而实验动物没有。这些结果与其他证据一致，即循环性腺激素会影响雌性大鼠母性攻击行为的发生。
