Department of Zoology, The University of British Columbia, Vancouver, British Columbia, Canada.
Comp Biochem Physiol B Biochem Mol Biol. 2013 Jan;164(1):2-9. doi: 10.1016/j.cbpb.2012.08.001. Epub 2012 Aug 7.
We examined the metabolic responses of the South American frog, Ceratophrys ornata, to laboratory-induced estivation. Whole-animal and mass-specific oxygen consumption rates (VO(2)) did not change during fasting or 56days of estivation, despite observing significant decreases in body mass. The maintenance of mass-specific metabolic rate at routine levels during estivation suggests that metabolic rate suppression is not a major response to estivation in this species. There was a significant decline in liver glycogen and a loss of adipose tissue mass during estivation, suggesting that both carbohydrate and lipid pathways are used to fuel metabolism during estivation. The activity of pyruvate dehydrogenase, an important regulator of carbohydrate oxidation, and carnitine palmitoyltransferase and 3-hydroxyacyl-CoA dehydrogenase, regulators of lipid oxidation, showed no significant change in activity in liver, heart, and muscle between estivating and active frogs. There was an increase in plasma osmolality, which is characteristic of estivating animals. Overall, our metabolic analysis of estivation in C. ornata indicates that this species does not employ a dramatic suppression metabolic rate to survive dehydration stress and that both endogenous carbohydrates and lipids are used as metabolic fuels.
我们研究了南美青蛙 Ceratophrys ornata 对实验室诱导的夏眠的代谢反应。尽管体重明显下降，但在禁食或 56 天的夏眠期间，整个动物和比氧耗率（VO2）并没有变化。在夏眠期间，维持常规水平的比代谢率表明代谢率抑制不是该物种夏眠的主要反应。在夏眠期间，肝糖原显著下降，脂肪组织质量减少，表明碳水化合物和脂质途径都被用来为夏眠期间的代谢提供燃料。丙酮酸脱氢酶（碳水化合物氧化的重要调节剂）和肉碱棕榈酰转移酶和 3-羟酰基辅酶 A 脱氢酶（脂质氧化的调节剂）的活性在肝、心和肌肉中在夏眠和活跃的青蛙之间没有明显变化。血浆渗透压升高，这是夏眠动物的特征。总的来说，我们对 C. ornata 夏眠的代谢分析表明，该物种不会通过显著抑制代谢率来应对脱水应激，并且内源性碳水化合物和脂质都被用作代谢燃料。
