Department of Biology, Princeton University, Princeton, New Jersey 08544, USA.
J Neuroendocrinol. 1989 Dec 1;1(6):407-13. doi: 10.1111/j.1365-2826.1989.tb00139.x.
Abstract Primiparous female hamsters (Mesocricetus auratus) were mated to proven breeders and stressed during early pregnancy. Females were housed singly throughout gestation except for Days 4, 5 and 6 when they were paired for ten-min intervals three times each day with another female matched for age, weight and day of pregnancy. Within each of the pairs, one female was consistently dominant to the other. Controls were exposed to a novel area instead of a conspecific. At parturition, all pups were counted, sexed and weighed. There were no significant differences between control and dominant females' litter sizes or sex ratios (defined as percentage male). Subordinate females produced significantly smaller litters than control or dominant dams and significantly lower sex ratios than control dams. Subordinates produced fewer males than control or dominant dams, but there were no differences in the number of females produced. The paraventricular nucleus (PVN) of the hypothalamus has been implicated as a relay center for the physiological response to stress. Bilateral lesions of the PVN were performed on another group of females and the same protocol described above was followed after the females recovered from surgery. When this 'stress relay center' was lesioned, subordinates did not show the significant deficits in litter size and sex ratio. Sham-operated females showed a similar response to social stress to that of intact females. These results suggest that subordinate dams produce smaller litters via selective resorption of males in utero and that the PVN may be a relay center for the mediation of this response.
摘要 将初产雌性金黄仓鼠（Mesocricetus auratus）与经证实的繁殖者交配，并在怀孕早期对其施加压力。除了妊娠第 4、5 和 6 天之外，雌性仓鼠在整个妊娠期间都单独饲养，在这三天中，它们每天与另一只年龄、体重和妊娠日匹配的雌性仓鼠配对 10 分钟，进行三次。在每对中，一只雌性仓鼠始终对另一只具有优势。对照组被暴露在一个新的区域，而不是与同物种接触。分娩时，对所有幼崽进行计数、性别鉴定和称重。对照组和优势组的幼崽数量或性别比例（定义为雄性百分比）没有显著差异。从属雌性的幼崽数量明显少于对照组或优势组的幼崽，性别比例也明显低于对照组的幼崽。从属组产生的雄性幼崽少于对照组或优势组的幼崽，但产生的雌性幼崽数量没有差异。下丘脑的室旁核（PVN）被认为是对压力的生理反应的中继中心。另一组雌性动物进行了双侧 PVN 损伤，在雌性动物从手术后恢复后，遵循了上述相同的方案。当这个“应激中继中心”被损伤时，从属组在幼崽数量和性别比例上没有表现出明显的缺陷。假手术组的雌性动物对社会压力的反应与完整组的雌性动物相似。这些结果表明，从属母鼠通过选择性吸收子宫内的雄性幼崽来产生较小的幼崽，而 PVN 可能是介导这种反应的中继中心。
