title: Human plasma beta-endorphin-like peptides: a rapid, high recovery extraction technique and validation of radioimmunoassay.
abstract: This is a report of the development, calibration, and validation of a series of techniques required to measure beta-endorphin (beta-END)-like immunoreactivity in human plasma, including sieve and affinity chromatography. The RIA, which uses the antibody Brenda, is very sensitive (IC50 = 5-15 fmol/tube at a final concentration of 1:40,000). The extraction process, which uses the Sep-Pak C18 cartridge (Waters Associates, Inc.), is simple and rapid and has a recovery rate of more than 90%. It extracts proopiomelanocortin, beta-lipotropin, and beta-END. Physiological validation was provided by the measurement of beta-END-like immunoreactivity in a pool of plasma of normal humans (2.25 fmol/ml plasma), two pregnant women at term (9.5 and 10.75 fmol/ml), and one patient with Nelson's disease (2 pmol/ml plasma).
mesh_terms: D000818:Animals; D000918:Antibody Specificity; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D004723:Endorphins / Q000097:blood* / Q000276:immunology / Q000302:isolation & purification; D005260:Female; D006801:Humans; D008297:Male; D009347:Nelson Syndrome / Q000097:blood; D010902:Pituitary Gland / Q000032:analysis; D010908:Pituitary Hormones, Anterior / Q000302:isolation & purification; D011247:Pregnancy; D011333:Pro-Opiomelanocortin; D011498:Protein Precursors / Q000302:isolation & purification; D011863:Radioimmunoassay; D051381:Rats; D013048:Specimen Handling; D001615:beta-Endorphin; D008083:beta-Lipotropin / Q000302:isolation & purification
chemical_list: D004723:Endorphins; D010908:Pituitary Hormones, Anterior; D011498:Protein Precursors; D001615:beta-Endorphin; D011333:Pro-Opiomelanocortin; D008083:beta-Lipotropin