细胞外碳酸氢盐缓冲系统对缺氧肌肉中无氧糖酵解的意义。

Significance of the extracellular bicarbonate buffer system to anaerobic glycolysis in hypoxic muscle.

Gesser H

Acta Physiol Scand. 1976 Sep;98(1):110-5. doi: 10.1111/j.1748-1716.1976.tb10309.x.

PMID:9777

Abstract

The influence of the carbon dioxide-bicarbonate buffer system on anaerobic energy production during severe hypoxia was studied in isolated right hemidiaphragms of rats.--2. When the tissue was incubated in a Ringer solution containing 25 mM HCO-3 aerated with 7% CO2 in N2 at pH 7.4, the lactate production and lactate content of the tissue increased.--3. At an extracellular (tissue bath) pH OF 6.9 the lactate production was stimulated when carbon dioxide and bicarbonate were changed to 19% and 25 mM, respectively. This stimulatory effect disappeared when these values were lowered to 7% and 7 mM.--4. At pH 7.4 the stimulatory effect of the carbon dioxide-bicarbonate system persisted when the buffer value was lowered from 60 to 3 mM by changing the system from an open (i.e. continuous gas equilibration) to a closed one (i.e. without any gas phase). Decreasing the glucose in the media from 22 to 0 mM reduced the lactate production and abolished the stimulatory effect of the carbon dioxide--bicarbonate system.--5. There was no direct effect of this system on the glycolytic enzymes (i.e. lactate production and activity of phosphofructokinase of homogenates).

摘要

在大鼠离体右半膈肌中研究了二氧化碳 - 碳酸氢盐缓冲系统对严重缺氧时无氧能量产生的影响。
当组织在含有25 mM HCO₃且用7% CO₂和N₂混合气体在pH 7.4条件下曝气的林格溶液中孵育时，组织的乳酸生成量和乳酸含量增加。
在细胞外（组织浴）pH为6.9时，当二氧化碳和碳酸氢盐分别变为19%和25 mM时，乳酸生成受到刺激。当这些值降至7%和7 mM时，这种刺激作用消失。
在pH 7.4时，通过将系统从开放（即连续气体平衡）变为封闭（即无任何气相），使缓冲值从60 mM降至3 mM，二氧化碳 - 碳酸氢盐系统的刺激作用仍然存在。将培养基中的葡萄糖从22 mM降至0 mM会降低乳酸生成并消除二氧化碳 - 碳酸氢盐系统的刺激作用。
该系统对糖酵解酶（即匀浆的乳酸生成和磷酸果糖激酶活性）没有直接影响。