title: Exercise increases sphingoid base-1-phosphate levels in human blood and skeletal muscle in a time- and intensity-dependent manner.
abstract: OBJECTIVE
  Sphingosine-1-phosphate (S1P) regulates cardiovascular function and plays an important role in muscle biology. We have previously reported that cycling exercise increased plasma S1P. Here, we investigated the effect of exercise duration and intensity on plasma and skeletal muscle S1P levels.
  
  
  METHODS
  In the first experiment, 13 male athletes performed a 60-min exercise at 65 % of VO2max and a graded exercise until exhaustion on a rowing ergometer. Samples of the venous blood were taken, and plasma, erythrocytes and platelets were isolated. In the second experiment, ten male moderately active subjects performed three consecutive periods of one-leg knee extension exercise (at 25, 55 and 85 % of the maximal workload). Muscle biopsies and blood samples from the radial artery and femoral veins were taken.
  
  
  RESULTS
  Under basal conditions, S1P was released from the leg, as its concentration was lower in the arterial than in the venous plasma (p < 0.01). Exercise until exhaustion increased plasma S1P and sphinganine-1-phosphate (SA1P) concentration (p < 0.05), whereas moderate-intensity exercise elevated only SA1P (p < 0.001). Although knee extension increased muscle S1P content (p < 0.05), it was not released but taken up across the leg during exercise. However, sphingosine was released from both working and resting leg at the highest workload (p < 0.05).
  
  
  CONCLUSIONS
  Plasma S1P concentration is elevated only by high-intensity exercise which results, at least in part, from increased availability of sphingosine released by skeletal muscle. In addition, exercise markedly affects S1P dynamics across the leg. We speculate that S1P may play an important role in adaptation of skeletal muscle to exercise.
authors.affiliation: Department of Physiology, Medical University of Białystok, Mickiewicza 2c, 15-222, Białystok, Poland, marcinb@umb.edu.pl.
authors.forename: Marcin
authors.initials: M
authors.lastname: Baranowski
authors.forename: Agnieszka U
authors.initials: AU
authors.lastname: Błachnio-Zabielska
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Charmas
authors.forename: Jørn W
authors.initials: JW
authors.lastname: Helge
authors.forename: Flemming
authors.initials: F
authors.lastname: Dela
authors.forename: Monika
authors.initials: M
authors.lastname: Książek
authors.forename: Barbara
authors.initials: B
authors.lastname: Długołęcka
authors.forename: Andrzej
authors.initials: A
authors.lastname: Klusiewicz
authors.forename: Adrian
authors.initials: A
authors.lastname: Chabowski
authors.forename: Jan
authors.initials: J
authors.lastname: Górski
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000328:Adult; D056352:Athletes; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008246:Lysophospholipids / Q000097:blood / Q000378:metabolism*; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism; D013997:Time Factors; D055815:Young Adult
chemical_list: D008246:Lysophospholipids; C060506:sphingosine 1-phosphate; D013110:Sphingosine