title: Effect of exercise on met-enkephalin in unfit and superfit individuals.
abstract: Twenty-four unfit volunteers and twenty-three superfit athletes were subjected to a progressive intensity treadmill exercise to total exhaustion in order to study the plasma met-enkephalin response to exercise. Blood samples were collected before and 5 min post-exercise. The basal met-enkephalin levels were significantly higher in the superfit individuals (180 fmol.ml-1) than in the unfit individuals (126 fmol.ml-1). Post-exercise the increase from basal levels of plasma met-enkephalin was significantly higher in the superfit athletes (180-278 fmol.ml-1) than in the unfit individuals (126-157 fmol.ml-1). The magnitude of the met-enkephalin responses to exercise therefore appears to be dependent on the amount of work performed and the degree of previous physical training. Peripherally circulating opioid peptides may, therefore, possibly play a role in the body's adaptation to exercise training.
authors.affiliation: Department of Pharmacology, University of Pretoria, South Africa.
authors.forename: K
authors.initials: K
authors.lastname: De Sommers
authors.forename: S F
authors.initials: SF
authors.lastname: Simpson
authors.forename: J M
authors.initials: JM
authors.lastname: Loots
authors.forename: E C
authors.initials: EC
authors.lastname: Meyer
authors.forename: A
authors.initials: A
authors.lastname: Dettweiler
authors.forename: H O
authors.initials: HO
authors.lastname: Daehne
mesh_terms: D000328:Adult; D004744:Enkephalin, Methionine / Q000097:blood*; D006801:Humans; D005082:Physical Exertion / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology*
chemical_list: D004744:Enkephalin, Methionine