title: The protein content of extracellular fluids and its relevance to the study of ionic regulation: net charge and colloid osmotic pressure.
abstract: 1. Protein net charge in blood plasma and haemolymph is relevant to overall anion-cation balance, Donnan equilibria, colloid osmotic pressures (COPs), buffering and liquid junction potentials, but its definition and measurement are not always straightforward. 2. Normal values of protein net charge in man and other animals are discussed, as is their dependence on pH. 3. Although it is clear that charge on a protein augments COP, the theory of COP is still incomplete. 4. The dependence of COP on protein and salt concentrations and on pH are therefore considered empirically. 5. Normal values for COP in various animals are given and the regulation of COP is discussed.
mesh_terms: D000136:Acid-Base Equilibrium; D000818:Animals; D003102:Colloids; D005110:Extracellular Space / Q000502:physiology*; D007477:Ions; D009997:Osmotic Pressure; D011506:Proteins / Q000502:physiology*
chemical_list: D003102:Colloids; D007477:Ions; D011506:Proteins