Rossing T H, Maffeo N, Fencl V
J Appl Physiol (1985). 1986 Dec;61(6):2260-5. doi: 10.1152/jappl.1986.61.6.2260.
We altered the concentration of plasma proteins in human blood in vitro by adding solutions with [Na+], [K+], and [Cl-] resembling those in normal blood plasma, either protein-free or with a high concentration of human albumin. After equilibrating the samples with a gas containing 5% CO2-12% O2-83% N2 at 37 degrees C, we measured pH, PCO2, and PO2; in separated plasma, we determined the concentrations of total plasma proteins and albumin and of the completely dissociated electrolytes (strong cations Na+, K+, Mg2+ and anions Cl-, citrate3-). With PCO2 nearly constant (mean = 35.5 Torr; coefficient of variation = 0.02), lowering plasma protein concentration produced a metabolic alkalosis, whereas increasing plasma albumin concentration gave rise to a metabolic acidosis. These acid-base disturbances occurred independently of a minor variation in the balance between the sums of strong cations and anions. We quantified the dependence of several acid-base variables in plasma on albumin (or total protein) concentration. Normal plasma proteins are weak nonvolatile acids. Although their concentration is not regulated as part of acid-base homeostasis, hypoproteinemia and hyperalbuminemia per se produce alkalosis and acidosis, respectively.
我们通过添加含有与正常血浆中[Na⁺]、[K⁺]和[Cl⁻]相似的溶液，在体外改变人血中血浆蛋白的浓度，这些溶液要么不含蛋白质，要么含有高浓度的人白蛋白。在37℃下用含有5% CO₂ - 12% O₂ - 83% N₂的气体平衡样品后，我们测量了pH、PCO₂和PO₂；在分离的血浆中，我们测定了总血浆蛋白、白蛋白以及完全解离的电解质（强阳离子Na⁺、K⁺、Mg²⁺和阴离子Cl⁻、柠檬酸根³⁻）的浓度。在PCO₂几乎恒定（平均值 = 35.5 Torr；变异系数 = 0.02）的情况下，降低血浆蛋白浓度会导致代谢性碱中毒，而增加血浆白蛋白浓度则会引起代谢性酸中毒。这些酸碱紊乱的发生与强阳离子和阴离子总和之间平衡的微小变化无关。我们量化了血浆中几个酸碱变量对白蛋白（或总蛋白）浓度的依赖性。正常血浆蛋白是弱的非挥发性酸。尽管它们的浓度不作为酸碱稳态的一部分进行调节，但低蛋白血症和高白蛋白血症本身分别会产生碱中毒和酸中毒。
