title: Responses of proenkephalin Peptide F to aerobic exercise stress in the plasma and white blood cell biocompartments.
abstract: Proenkephalin Peptide F [107-140] is an enkephalin-containing peptide found predominantly within the adrenal medulla, co-packaged with epinephrine within the chromaffin granules. In vivo studies indicate that Peptide F has classic opioid analgesia effects; in vitro studies suggest potential immune cell interactions. In this investigation we examined patterns of Peptide F concentrations in different bio-compartments of the blood at rest and following sub-maximal cycle exercise to determine if Peptide F interacts with the white blood cell (WBC) bio-compartment during aerobic exercise. Eight physically active men (n=8) performed sub-maximal (80-85% V˙O2peak) cycle ergometer exercise for 30 min. Plasma Peptide F and WBC Peptide F immunoreactivity were examined pre-exercise, mid-exercise and immediately post-, 5-min post-, 15-min post-, 30-min post- and 60-min post-exercise and at similar time-points during a control condition (30 min rest). Peptide F concentrations significantly (p<0.05) increased at 5 and 60 min post-exercise, compared to pre-exercise concentrations. No significant increases in Peptide F concentrations in the WBC fraction were observed during or after exercise. However, a significant decrease was observed at 30 min post-exercise. An ultradian pattern of Peptide F distribution was apparent during rest. Furthermore, concentrations of T cells, B cells, NK cells, and total WBCs demonstrated significant changes in response to aerobic exercise. Data indicated that Peptide F was bound in significant molar concentrations in the WBC fraction and that this biocompartment may be one of the tissue targets for binding interactions. These data indicate that Peptide F is involved with immune cell modulation in the white blood circulatory biocompartment of blood.
authors: Human Performance Laboratory, Department of Kinesiology, University of Connecticut, Storrs, CT 06269, United States. William.Kraemer@uconn.edu
authors: William J
authors: WJ
authors: Kraemer
authors: Maren S
authors: MS
authors: Fragala
authors: Wendy R H Beijersbergen
authors: WR
authors: van Henegouwen
authors: Scott E
authors: SE
authors: Gordon
authors: Jill A
authors: JA
authors: Bush
authors: Jeff S
authors: JS
authors: Volek
authors: N Travis
authors: NT
authors: Triplett
authors: Courtenay
authors: C
authors: Dunn-Lewis
authors: Brett A
authors: BA
authors: Comstock
authors: Tunde K
authors: TK
authors: Szivak
authors: Shawn D
authors: SD
authors: Flanagan
authors: David R
authors: DR
authors: Hooper
authors: Hui-Ying
authors: HY
authors: Luk
authors: Andrea M
authors: AM
authors: Mastro
mesh_terms: D000328:Adult; D001402:B-Lymphocytes / Q000378:metabolism; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives* / Q000097:blood; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007694:Killer Cells, Natural / Q000378:metabolism; D007773:Lactates / Q000097:blood; D007962:Leukocytes / Q000378:metabolism*; D008297:Male; D011498:Protein Precursors / Q000097:blood*; D013312:Stress, Physiological; D013601:T-Lymphocytes / Q000378:metabolism; D055815:Young Adult
chemical_list: D007773:Lactates; D011498:Protein Precursors; D004744:Enkephalin, Methionine; C036452:peptide F