title: An ion exchange chromatography and radioimmunoassay procedure for measuring opioid peptides and substance P.
abstract: The measurements of peptides of the enkephalin, dynorphin and substance P systems is complicated by the number of possible precursor fragments and degradation products that might cross-react with the antisera. By using an ion-exchanger step before radioimmunoassay we can reduce the possibility that observed peptide levels are due to precursors or metabolites. The ion-exchanger method runs with good recovery and its main advantage is that many samples can be run in parallel. The recovery from the ion-exchanger was similar using two different homogenizing media, whereas the measured endogenous levels of [Met] and [Leu]enkephalin were 3-4 fold higher with 1M acetic acid than when a 1:1 MeOH/HCl mixture was used for tissue extraction.
mesh_terms: D000085:Acetates; D000818:Animals; D001923:Brain Chemistry; D002852:Chromatography, Ion Exchange / Q000379:methods*; D004723:Endorphins / Q000032:analysis*; D004743:Enkephalin, Leucine / Q000032:analysis; D004744:Enkephalin, Methionine / Q000032:analysis; D000432:Methanol; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D013373:Substance P / Q000032:analysis*
chemical_list: D000085:Acetates; D004723:Endorphins; D013373:Substance P; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; D000432:Methanol