Pharmacological and immunological characterization of the Leu5 analogue of human beta-endorphin.
The potencies of beta h-endorphin, Met (O)5-beta h-endorphin, and synthetic Leu5-beta h-endorphin have been compared in three bioassays of opioid activity, and in two radioimmunoassays. In all assays, a peptide isolated from hemodialysates from a psychotic patient behaved like Leu5-beta h-endorphin; it has been distinguished unambiguously from beta h-endorphin and Met(O)5-beta h-endorphin. Leu5-beta h-endorphin was one-fifth as potent as beta h-endorphin in guinea pig ileum myenteric plexus, but was only slightly less active in mouse vas deferens and in guinea pig brain opiate receptor binding assay. The low cross-reactivity of Leu5-beta h-endorphin relative to beta h-endorphin with an antiserum raised to beta-endorphin suggests that the preferred solution conformations of these peptides are different. In all bioassays beta h-endorphin was 2- to 3-fold less potent than beta c-endorphin.
D000818:Animals; D001921:Brain / Q000378:metabolism; D004723:Endorphins / Q000097:blood / Q000378:metabolism / Q000494:pharmacology*; D005769:Gastrointestinal Motility / Q000187:drug effects; D006168:Guinea Pigs; D006801:Humans; D007082:Ileum / Q000187:drug effects; D008297:Male; D051379:Mice; D008968:Molecular Conformation; D009270:Naloxone / Q000494:pharmacology; D011618:Psychotic Disorders / Q000097:blood; D011863:Radioimmunoassay; D011957:Receptors, Opioid / Q000187:drug effects / Q000378:metabolism; D012964:Sodium / Q000494:pharmacology; D014649:Vas Deferens / Q000187:drug effects
D004723:Endorphins; D011957:Receptors, Opioid; D009270:Naloxone; D012964:Sodium