title: The effect of surgery on plasma beta-endorphin and methionine-enkephalin.
abstract: Seven women undergoing abdominal hysterectomy under halothane and nitrous oxide analgesia had plasma samples taken before, during and after surgery for assay of adrenocorticotrophin (ACTH), beta-endorphin, beta-lipotrophin and methionine (Met)-enkephalin immunoreactivity. Plasma ACTH, beta-endorphin and beta-lipotrophin all rose in parallel from the start of surgery and were unaffected by postoperative opiate analgesia. Plasma Met-enkephalin concentrations did not change significantly during the course of the surgery and immediate post-operative period, although the variance of the samples increased at the time of the first skin incision. These data indicate that the stress of surgery and post-operative pain, while producing marked elevations of proopiomelanocortin-derived peptides, are not associated with changes in plasma Met-enkephalin. These data exclude a role for circulating Met-enkephalin in the modulation of surgical pain but do not exclude such a role for beta-endorphin.
authors.forename: R
authors.initials: R
authors.lastname: Smith
authors.forename: G M
authors.initials: GM
authors.lastname: Besser
authors.forename: L H
authors.initials: LH
authors.lastname: Rees
mesh_terms: D000701:Analgesics, Opioid / Q000627:therapeutic use; D004723:Endorphins / Q000097:blood*; D004744:Enkephalin, Methionine / Q000097:blood*; D005260:Female; D006801:Humans; D007044:Hysterectomy; D008875:Middle Aged; D010149:Postoperative Pain / Q000097:blood / Q000188:drug therapy; D011863:Radioimmunoassay; D001615:beta-Endorphin
chemical_list: D000701:Analgesics, Opioid; D004723:Endorphins; D004744:Enkephalin, Methionine; D001615:beta-Endorphin