Donohoe P H, Boutilier R G
Department of Zoology, University of Cambridge, UK.
Respir Physiol. 1998 Mar;111(3):325-36. doi: 10.1016/s0034-5687(97)00125-4.
Aerobic metabolic rates (MO2) and respiratory quotients (RQ = MCO2/MO2) were measured in hypoxic frogs, hibernating underwater for up to 90 days at 3 degrees C. After 3 months of submergence at a PO2 of 50 mmHg, MO2 levels were 25% of those seen prior to hibernation. In progressive hypoxia, a gradual shift in RQ from 0.85 to 1.0 signaled an increasing reliance upon carbohydrate metabolism. Moreover, the glycogen concentrations of skeletal muscle, liver and heart of hypoxic frogs were more rapidly depleted than in their normoxic counterparts. A plasma lactacidosis revealed that the hypoxic animals recruited anaerobiosis to fuel a large 'Pasteur effect'. Throughout all stages of hypoxia, cellular ATP levels were maintained homeostatic. The ability to depress metabolic rate such that ATP demands can be met by oxidative phosphorylation in an oxygen limited environment is the key to the frogs' overwintering survival.
在3℃下于水下冬眠长达90天的低氧青蛙中测量了有氧代谢率（MO2）和呼吸商（RQ = MCO2/MO2）。在PO2为50 mmHg的情况下浸没3个月后，MO2水平为冬眠前的25%。在进行性低氧状态下，RQ从0.85逐渐转变为1.0，这表明对碳水化合物代谢的依赖增加。此外，低氧青蛙的骨骼肌、肝脏和心脏中的糖原浓度比常氧青蛙的糖原浓度消耗得更快。血浆乳酸酸中毒表明，低氧动物利用无氧呼吸来推动巨大的“巴斯德效应”。在低氧的所有阶段，细胞ATP水平都保持稳定。在氧气有限的环境中降低代谢率，使ATP需求能够通过氧化磷酸化来满足的能力是青蛙越冬生存的关键。
