Ahlqvist Johan
Department of Pathology, University of Helsinki, Finland.
J Appl Physiol (1985). 2004 Feb;96(2):762-4. doi: 10.1152/japplphysiol.00880.2003.
The colloid or protein osmotic pressure (Pi) is a function of protein molarity (linear) and of Donnan and other effects. Albumin is the major osmotic protein, but also globulins influence Pi. Equations based on concentrations of albumin and nonalbumin (globulin concentration + fibrinogen concentration) protein approximate Pi better than albumin alone. Globulins have a wide range of molecular weights, and a 1956 diagram indicated that Pi of globulin fractions decreased in the order alpha1-, alpha2-, beta-, and gamma-globulin. The molecular weight of the serum protein fractions had been extrapolated, so van't Hoff's law and nonlinear regression analysis of the curves permitted expression of the diagram as an equation: product Pi(s,Ott,2 degrees C,cmH2O)=x(alb)(0.338C(tot)+0.00339C(tot)(2))+x(alpha1)(0.518C(tot)+0.0107C(tot)(2))+x(alpha2)(0.203C(tot)+0.00155C(tot)(2))+x(beta)(0.187C(tot)+0.000577C(tot)(2))+x(gamma)(0.161C(tot)+0.000223C(tot)(2)), where Pi(s,Ott,2 degrees C,cmH2O) is Pi of serum at 2 degrees C (in cmH2O) computed from the 1956 diagram, C(tot) is the concentration (g/l) of total protein in serum, and x(alb), x(alpha1), x(alpha2), x(beta), and x(gamma) are the fractions of albumin, alpha1-, alpha2-, beta-, and gamma-globulin, respectively. At one and the same concentration of fractions, Pi("Ott") decreases in the order alpha1-globulin, albumin, alpha2-globulin, beta-globulin, and gamma-globulin.
胶体或蛋白质渗透压（Pi）是蛋白质摩尔浓度（呈线性关系）以及唐南效应和其他效应的函数。白蛋白是主要的渗透蛋白，但球蛋白也会影响Pi。基于白蛋白和非白蛋白（球蛋白浓度 + 纤维蛋白原浓度）浓度的方程比仅基于白蛋白的方程能更好地估算Pi。球蛋白的分子量范围很广，1956年的一张图表表明球蛋白各组分的Pi按α1 -、α2 -、β - 和γ - 球蛋白的顺序递减。血清蛋白各组分的分子量已通过外推得出，因此范特霍夫定律和曲线的非线性回归分析使得该图表可以表示为一个方程：产物Pi（s，Ott，2℃，cmH₂O）=x（alb）（0.338C（tot）+0.00339C（tot）²）+x（α1）（0.518C（tot）+0.0107C（tot）²）+x（α2）（0.203C（tot）+0.00155C（tot）²）+x（β）（0.187C（tot）+0.000577C（tot）²）+x（γ）（0.161C（tot）+0.000223C（tot）²），其中Pi（s，Ott，2℃，cmH₂O）是根据1956年图表计算得出的2℃时血清的Pi（单位为cmH₂O），C（tot）是血清中总蛋白的浓度（g/l），x（alb）、x（α1）、x（α2）、x（β）和x（γ）分别是白蛋白、α1 -、α2 -、β - 和γ - 球蛋白的组分比例。在各组分浓度相同的情况下，Pi（“Ott”）按α1 - 球蛋白、白蛋白、α2 - 球蛋白、β - 球蛋白和γ - 球蛋白的顺序递减。
