Dark J, Miller D R, Zucker I
Department of Psychology, University of California, Berkeley 94720, USA.
Am J Physiol. 1996 Jun;270(6 Pt 2):R1240-3. doi: 10.1152/ajpregu.1996.270.6.R1240.
We tested the hypothesis that continued secretion of gonadal steroids is necessary to suppress hibernation in male golden-mantled ground squirrels in the weeks after the terminal arousal in spring. Juvenile and adult males were gonadectomized or sham gonadectomized 1 wk after the terminal arousal; 64% of castrated and none of the shamcastrated animals resumed hibernation. Latency to resumption of torpor was 9 +/- 2 days from the time of castration, and squirrels underwent 4.3 +/- 0.9 bouts before permanently regaining euthermia. Among squirrels that resumed hibernation, bout duration was significantly shorter and torpor was shallower after castration. Castration as late as 3 wk after the terminal arousal reinstated hibernation. We suggest that the terminal arousal of male squirrels in the spring is provoked by a steroid-independent mechanism similar to that operating earlier in the hibernation season; abandonment of hibernation is contingent on concomitant sustained increases in androgen secretion during the first few weeks of euthermia.
在春季最后一次觉醒后的数周内，性腺类固醇持续分泌对于抑制雄性金背地松鼠冬眠是必要的。在最后一次觉醒1周后，对幼年和成年雄性松鼠进行去势或假去势手术；64%的去势动物恢复了冬眠，而假去势动物无一恢复冬眠。从去势时起，恢复蛰伏的潜伏期为9±2天，松鼠在永久恢复正常体温前经历了4.3±0.9个冬眠周期。在恢复冬眠的松鼠中，去势后冬眠周期持续时间显著缩短，蛰伏程度也变浅。在最后一次觉醒后3周进行去势手术，仍可使松鼠恢复冬眠。我们认为，春季雄性松鼠的最后一次觉醒是由一种与冬眠季节早期作用机制类似的非类固醇依赖机制引发的；放弃冬眠取决于在正常体温的最初几周内雄激素分泌同时持续增加。
