title: Moderate exercise triggers both priming and activation of neutrophil subpopulations.
abstract: We investigated how moderate exercise affects neutrophil microbicidal activity and whether exercise-induced responses are associated with changes in growth hormone (GH) secretion. Biological fluctuations were controlled for and GH secretion was manipulated by glucose ingestion. In eight men, 1 h of moderate exercise increased intracellular H2O2 generation in response to phorbol 12-myristate 13-acetate stimulation by threefold (P = 0.025) and complement receptor expression by 20% (P = 0.045). These responses were accompanied by a twofold increase in the plasma concentration of elastase, a marker of neutrophil activation in vivo. The plasma concentration of GH increased 10-fold after exercise, but this was reduced to 3-fold by glucose ingestion (P < 0.001), which also blunted elastase release (P < 0.001). Although the magnitude of H2O2 generation increased in proportion to the increase in plasma GH concentration, it declined progressively once this exceeded 20 ng/ml. The net response of neutrophils to exercise may represent a balance between the individual responses of subpopulations that are unaffected, primed, or fully activated by circulating mediators that respond to exercise and to dietary glucose intake.
authors.affiliation: Division of Biochemistry and Molecular Biology, School of Life Sciences, Faculty of Science, Australian National University, Canberra, Australia.
authors.forename: J A
authors.initials: JA
authors.lastname: Smith
authors.forename: A B
authors.initials: AB
authors.lastname: Gray
authors.forename: D B
authors.initials: DB
authors.lastname: Pyne
authors.forename: M S
authors.initials: MS
authors.lastname: Baker
authors.forename: R D
authors.initials: RD
authors.lastname: Telford
authors.forename: M J
authors.initials: MJ
authors.lastname: Weidemann
mesh_terms: D000328:Adult; D005434:Flow Cytometry; D013006:Growth Hormone / Q000097:blood; D006801:Humans; D019272:Leukocyte Elastase / Q000097:blood; D008027:Light; D008297:Male; D009504:Neutrophils / Q000502:physiology*; D010196:Pancreatic Elastase / Q000097:blood; D005082:Physical Exertion; D011971:Receptors, Immunologic / Q000378:metabolism; D016897:Respiratory Burst; D012542:Scattering, Radiation
chemical_list: D011971:Receptors, Immunologic; C091196:opsonin receptor; D013006:Growth Hormone; D010196:Pancreatic Elastase; D019272:Leukocyte Elastase