Heterogeneity of corticotropin-immunoreactive compounds in human body fluids

Using reversed-phase "high-performance" liquid chromatography and hydrophilic ion-pairing reagents, we studied the chromatographic profiles of corticotropin immunoreactivities in human plasma, cerebrospinal fluid, and urine. The chromatographic system we applied provides excellent separation of peptide molecules, with reproducibility (CV) of retention times better than 0.5%, and makes feasible the subsequent immunological quantitation of eluted fractions. Profiles of corticotropin immunoreactivities exhibited several chemically different compounds in each of the three body fluids studied. A considerable portion of these immunoreactive compounds is more hydrophilic and probably of lower molecular mass than the human corticotropin 1-39 molecule itself. These hydrophilic molecules are more predominant in urine and plasma than in cerebrospinal fluid.