Passmore J C, Pfeiffer E W, Templeton J R
J Exp Zool. 1975 Apr;192(1):83-6. doi: 10.1002/jez.1401920110.
Hibernation was induced in Columbian ground squirrels by placing them in refrigerated cages equipped with urine-collection pans. On arousal, urine and blood were collected from each animal, which was then allowed to reenter hibernation. After several days the animal was sacrificed and bladder urine and another blood sample were taken. In addition, four active non-hibernating ground squirrels were placed in a cage at room temperature with neither food or water. Urine was collected at 9 and 26 hours and blood was collected at 0 and 26 hours. Although only seven of ten hibernating squirrels had a higher blood-urea level when sacrificed than during the previous arousal, the other three had very high levels in the arousal period and probably further excreted urea before entering hibernation. When total body urea was calculated on a body weight basis, all except one animal showed a greater level of urea during hibernation than in the previous arousal. During their period of dehydration, the non-hibernating summer squirrels showed a marked decrease in blood urea. The osmotic concentration of the urine from these squirrels was due less to urea than that excreted during arousal by hibernating squirrels. Thus, it appears that urea accumulates in the blood during hibernation and is excreted in the urine during arousal.
通过将哥伦比亚地松鼠放置在配备尿液收集盘的冷藏笼中诱导其进入冬眠状态。在唤醒时，从每只动物身上采集尿液和血液，然后让其重新进入冬眠状态。几天后，处死动物并采集膀胱尿液和另一份血液样本。此外，将四只活跃的非冬眠地松鼠放置在室温下的笼子里，不给食物和水。在9小时和26小时时收集尿液，在0小时和26小时时收集血液。尽管在处死时，十只冬眠松鼠中只有七只的血尿素水平高于前一次唤醒时，但另外三只在唤醒期血尿素水平非常高，可能在进入冬眠前进一步排泄了尿素。当以体重为基础计算全身尿素时，除一只动物外，所有动物在冬眠期间的尿素水平都高于前一次唤醒时。在脱水期间，非冬眠的夏季松鼠血尿素显著降低。这些松鼠尿液的渗透浓度中尿素所占比例低于冬眠松鼠唤醒时排泄的尿液。因此，似乎尿素在冬眠期间在血液中积累，并在唤醒时随尿液排出。
