[Interpretations of laboratory test data on serum protein binding].
Serum proteins that are important in the serum protein binding of drugs are human serum albumin (HSA) and alpha1-acid glycoprotein (AGP). Several binding sites exist on HSA and AGP molecules. HSA, AGP, free fatty acid (FFA), blood urea nitrogen (BUN) and bilirubin, which can all be determined by laboratory test, affect the binding capacities of binding sites on these proteins. The increase and decrease of HSA and AGP influence the binding capacities of all binding sites. As an additional influence on the binding sites on protein molecules, the increment of FFA decrease the binding capacity of site II, while binding capacity of site I is enhanced by FFA. Increase in bilirubin remarkably decreases the binding capacity of site I. BUN data are associated with the amounts of several uremic toxins, 3-carboxy-4-methyl-5-propyl-2-furanpropanate (CMPF), indole-3-acetate (IA), indoxyl sulfate (IS) and hippurate (HA). With CMPF, the binding capacity of site I is decreased, while IA, IS, HA contribute to the binding inhibition of site II of HSA. If we can monitor binding capacities of binding sites of HSA and AGP, laboratory test data can be interpreted from a pharmaceutical perspective regarding protein binding, because changes in laboratory test data that are endogenous substance concentrations have an influence on the binding capacities of those binding sites.
Takamura
Norito
N
Second Department of Clinical Pharmacy, School of Pharmaceutical Sciences, Kyushu University of Health and Welfare, Nobeoka City, Japan. noritotaka@phoenix.ac.jp
Tokunaga
Jin
J
Arimori
Kazuhiko
K
D001665:Binding Sites; D019411:Clinical Laboratory Techniques; D006801:Humans; D009961:Orosomucoid / Q000378:metabolism*; D010599:Pharmacokinetics; D011485:Protein Binding; D012709:Serum Albumin / Q000378:metabolism*
D009961:Orosomucoid; D012709:Serum Albumin