These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: The in vivo effect of melatonin on cellular activation processes in human blood during strenuous physical exercise.
    Author: Johe PD, Østerud B.
    Journal: J Pineal Res; 2005 Oct; 39(3):324-30. PubMed ID: 16150115.
    Abstract:
    Melatonin has been reported to have anti- as well as pro-inflammatory properties. Because physical stress is associated with the activation of blood cells, the present study examines melatonin's role in exercise-induced cell activation processes. Eight healthy volunteers (aged 20-62 yr, mean = 31), exercised on an 'Ergometric' bike for 30 min at 80% of their calculated maximum pulse rate. Blood samples were taken just before melatonin administration, directly after exercise, and 2 hr after exercise completion. Cytokine and eicosanoid parameters were measured in plasma from blood stimulated with lipopolysaccharide (LPS) for 2 hr whereas tissue factor (TF) activity was measured in isolated monocytes. Melatonin significantly decreased LPS-induced TF activity by 48% (P < 0.01) directly after exercise, and a 44% reduction was seen 2 hr later (P < 0.02). Furthermore, melatonin significantly reduced the lymphocyte count rise produced directly after exercising by more than 30% (P < 0.01). A trend was also seen for melatonin suppressing the increase of WBC by around 10% and to strengthen the platelet increase by about 8% after physical stress. Melatonin also significantly lowered RBC and hemoglobin counts by 5 and 3-4% during exercise (P < 0.005 and <0.02 respectively). Two hours after exercise, melatonin tended to lower leukotriene B4 levels by 30%. Interleukin-8 and tumor necrosis factor-alpha levels tended to be lower in individuals who had taken melatonin following hard physical activity and a larger sample size may show significance. Thromboxane B2 production seemed unaffected by melatonin during exercise. In conclusion, in vivo intake of melatonin appears to suppress LPS-induced activation of monocytes in whole blood reactions associated with physical exercise and facilitates the down-regulation of inflammatory mediators.
    [Abstract] [Full Text] [Related] [New Search]