Brooks S P, Storey K B
Department of Biology, Carleton University, Ottawa, Ontario, Canada.
Biochem Mol Biol Int. 1994 Dec;34(6):1253-8.
Organ slices from the turtle Trachemys scripta elegans were incubated under aerobic and anoxic conditions to examine the effect of protein kinase (PrK) second messengers in potentiating the biochemical responses to anoxia exposure. Incubating liver slices from aerobic animals under anoxic conditions produced biochemical changes exactly similar to those observed in vivo: phosphofructokinase (PFK) was more sensitive to citrate inhibition and the percentage of glycogen phosphorylase (GP) in the active a form increased. On the other hand, incubating brain and heart tissue slices under anoxic conditions produced no changes in PFK and GP kinetic constants. Addition of PrK second messengers (dibutyryl-cAMP or Ca2+ plus phorbol myristate acetate) to the incubated tissues did not promote anoxia-associated changes in aerobically incubated tissues nor did they prevent anoxia-associated changes in anaerobically incubated tissues. These results suggest that unidentified external hormonal signals mediate heart and brain responses to anoxia. It is also apparent that cAMP and Ca2+ plus phospholipid do not play a role in bringing about the anoxia-induced changes in PFK, GP and fructose 2,6-bisphosphate in liver of turtles.
将来自秀丽锦龟的器官切片在有氧和无氧条件下进行孵育，以研究蛋白激酶（PrK）第二信使在增强对缺氧暴露的生化反应中的作用。在无氧条件下孵育来自有氧动物的肝脏切片，会产生与体内观察到的完全相似的生化变化：磷酸果糖激酶（PFK）对柠檬酸抑制更敏感，且糖原磷酸化酶（GP）的活性a形式的百分比增加。另一方面，在无氧条件下孵育脑和心脏组织切片，PFK和GP动力学常数没有变化。向孵育的组织中添加PrK第二信使（二丁酰环磷酸腺苷或Ca2+加佛波醇肉豆蔻酸酯），既不会促进在有氧条件下孵育的组织中与缺氧相关的变化，也不会阻止在无氧条件下孵育的组织中与缺氧相关的变化。这些结果表明，未确定的外部激素信号介导心脏和大脑对缺氧的反应。同样明显的是，环磷酸腺苷和Ca2+加磷脂在引起海龟肝脏中PFK、GP和果糖2,6-二磷酸的缺氧诱导变化中不起作用。
