The effect of exercise on the granulocyte response to isoproterenol in the trained athlete and unconditioned individual.

Many factors will influence the tissue response to catecholamine stimulation. Isolated human granulocytes (PMNs) release the lysosomal enzyme beta-glucuronidase following incubation with complement-activated zymosan particles. Isoproterenol, histamine, and prostaglandin E1 (PGE1) inhibit this PMN release of beta-glucuronidase. The effect of exercise on this in vitro granulocyte response was studied in two groups: highly conditioned marathon runners (n = 6) and unconditioned subjects (n = 7). A 13-km run did not produce leukocytosis in the highly conditioned marathon runners and the granulocyte response to isoproterenol was unchanged in cells obtained immediately following the run. In contrast, the seven unconditioned subjects exercised to a maximal response on the treadmill. Following exercise there was an increase in plasma catecholamines, a significant leukocytosis, and granulocytes from the immediate postexercise period responded less well to isoproterenol.