Fraley D S, Adler S
Kidney Int. 1976 Apr;9(4):333-43. doi: 10.1038/ki.1976.39.
pH and bicarbonate affect many metabolic reactions but each may change independently. To study bicarbonate's effect onplasma potassium, blood bicarbonate in normal, hypokalemic or hyperkalemic rats was either maintained constant, lowered by hydrochloric acid or raised by sodium bicarbonate administraion. Blood pH was maintained constant by changing PCO2. In normokalemia lowering bicarbonate increased plasma potassium 2.0mEq above values obtained in the other groups. To eliminate urinary potassium losses, experiments were also performed in rats with bilateral ureteral ligation. Again, plasma potassium concentration rose significantly more in the lowered bicarbonate group. Similarly, in hypokalemia, plasma potassium rose 1.2 and 0.4mEq in the lowered and unchanged groups, but fell 0.2mEq/liter in the elevated group. Differences could not be ascribed to renal potassium losses as potassium excretion was essentially zero in each group. In hyperkalemia, plasma potassium concentration remained elevated for 150 min in the lowered bicarbonate group but fell 1.3 and 2.0mEq in the unchanged and elevated groups, respectively. Urinary potassium losses in the three groups were statistically identical. In all experiments blood pH was maintained unchanged during the experiment. The data show that bicarbonate, independent of blood pH, alters transcellular potassium distribution suggesting the usefulness of bicarbonate therapy in hyperkalemia even at a compensated blood pH.
pH值和碳酸氢盐会影响许多代谢反应，但二者可能独立变化。为研究碳酸氢盐对血浆钾的影响，维持正常、低钾血症或高钾血症大鼠的血液碳酸氢盐恒定、通过盐酸降低或通过给予碳酸氢钠升高。通过改变PCO₂维持血液pH值恒定。在正常血钾情况下，降低碳酸氢盐会使血浆钾比其他组的值高出2.0mEq。为消除尿钾流失，还对双侧输尿管结扎的大鼠进行了实验。同样，在降低碳酸氢盐的组中，血浆钾浓度升高更为显著。类似地，在低钾血症中，降低组和不变组的血浆钾分别升高1.2和0.4mEq，但升高组下降0.2mEq/升。差异不能归因于肾钾流失，因为每组的钾排泄基本为零。在高钾血症中，降低碳酸氢盐组的血浆钾浓度在150分钟内保持升高，但不变组和升高组分别下降1.3和2.0mEq。三组的尿钾流失在统计学上相同。在所有实验中，实验期间血液pH值保持不变。数据表明，碳酸氢盐独立于血液pH值改变细胞间钾分布，这表明即使在血液pH值代偿的情况下，碳酸氢盐治疗在高钾血症中也是有用的。
