Beta-endorphin (1-31) in the plasma of male volunteers undergoing physical exercise.
beta-Endorphin is an opioid peptide representing the C-terminal 31 amino acid residue fragment of proopiomelanocortin (POMC). The release of beta-endorphin from the pituitary into the cardiovascular compartment under physical or emotional stress has been frequently reported. However, besides beta-endorphin (1-31), nine acetylated or non-acetylated beta-endorphin analogues exist - in addition to N-terminally elongated beta-endorphin derivatives such as beta-lipotropin (beta-LPH). Since conventional radioimmunoassays (RIAs) and even commercially available two site-RIAs pick up at least some of those beta-endorphin derivatives, only "beta-endorphin immunoreactive materials" and not authentic beta-endorphin have been determined in those studies. We have developed a highly specific two site-RIA for beta-endorphin (1-31), which does not cross-react with all beta-endorphin derivatives known to occur as yet. Using this RIA as well as further assays for determination of beta-endorphin (1-31), beta-endorphin immunoreactive material (IRM), ACTH and Cortisol in the plasma of 14 volunteers upon intensive physical exercise, we found authentic beta-endorphin only in about 50% of the plasma samples, representing therein only a minor portion of the beta-endorphin IRM.
Harbach
H
H
Abt. Anaesthesiologie und Operative Intensivmedizin, Giessen, Germany. heinz.harbach@chiru.med.uni-giessen.de
Hell
K
K
Gramsch
C
C
Katz
N
N
Hempelmann
G
G
Teschemacher
H
H
D000324:Adrenocorticotropic Hormone / Q000097:blood; D000328:Adult; D015444:Exercise / Q000502:physiology*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D008297:Male; D010446:Peptide Fragments / Q000097:blood*; D001615:beta-Endorphin / Q000097:blood*
D010446:Peptide Fragments; D001615:beta-Endorphin; D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone