Abstract
The present study was designed to test the hypothesis that the exercise-induced changes
in blood mononuclear cell (BMNC) subsets, BMNC proliferative responses and lymphokine
activated killer (LAK) cell activity are mediated by increased epinephrine concentrations.
Healthy male volunteers 1) exercised on a bicycle ergometer (75% of V̇O2max, 1 h) and 2) on another day were given epinephrine as an intravenous infusion
to obtain plasma epinephrine concentrations comparable with those seen during exercise.
Blood samples were collected in the basal state, during the last minutes of exercise
or epinephrine infusion and 2h later. During both perturbations the%CD3+ and%CD4+ T cells declined and the%CD16+ NK cells increased. Two h afterwards the CD14+ monocytes increased, while no changes were observed in%CD8+ T cells or%CD20+ T cells. The phytohemagglutinin (PHA) response declined during both epinephrine infusion
and exercise experiments. The changes in interleukin-2 (IL-2) effect on proliferation
and cytotoxic activity (LAK cell activity) were more pronounced in exercise experiments
than during epinephrine. Exercise and epinephrine caused increase in concentrations
of lymphocytes and neutrophils, but the changes were more pronounced in exercise experiments.
The results indicate that, in response to physical exercise, the rise in plasma epinephrine
may contribute to the changes in cellular immunity.
Key words
Physical exercise - epinephrine - stress hormones - lymphokine activated killer cells
- lymphocytes - blood mononuclear cell subsets - proliferative responses - interleukin
2
