ABSTRACT
It is well recognized that many substances of both endogenous and exogenous origin are present in the bloodstream as complexes with certain plasma macromolecules. Such binding is generally reversible, and therefore it serves as a carrier mechanism for the functionally active unbound ligand. Additionally, the distribution and elimination of a compound may be limited by plasma binding, and thus the interaction often functions to maintain the presence of the ligand within the body. The extent of binding is dependent not only on the concentration of the ligand, but also the amount of macromolecule to which binding occurs and its affinity, and the presence of competitive binding substances. Nutritional status, together with disease states and other factors, may, therefore, affect plasma binding by changing any of the latter three determinants.
