title: beta-Endorphin immunoreactive materials in human plasma determined by a multiple radioimmunoassay system.
abstract: Extracts of plasma obtained from adult humans before and immediately after physical stress were subjected to high pressure liquid chromatography (HPLC); extracts or HPLC fractions, resp., were analysed for the presence of human beta-endorphin (beta H-endorphin) or fragments thereof by several radioimmunoassays using antibodies directed against the C-terminus and two "middle" regions of beta H-endorphin. Using an antibody ("Don Antonio") apparently directed against a beta H-endorphin fragment including positions 17 to 22 or somewhat adjacent regions, concentrations of beta H-endorphin immunoreactivity were found to be in the well-known range under normal conditions and to increase after physical stress. However, only a minor portion of this material proved to be identical with beta H-endorphin, whereas the major portion behaved like a smaller fragment thereof. In addition, high amounts of an immunoreactive material obviously containing a C-terminal sequence of beta H-endorphin were found, indicating the presence of an immunologically relevant beta H-endorphin fragment in the plasma.
mesh_terms: D000328:Adult; D002851:Chromatography, High Pressure Liquid; D003429:Cross Reactions; D004723:Endorphins / Q000097:blood*; D006801:Humans; D008297:Male; D011863:Radioimmunoassay / Q000379:methods; D013312:Stress, Physiological / Q000097:blood; D001615:beta-Endorphin
chemical_list: D004723:Endorphins; D001615:beta-Endorphin