Indomethacin does not alter the natural killer cell response to 2. 5 hours of running (revised manuscript #a1185-4). Nieman, D. C., J. C. Ahle, D. A. Henson, B. J. Warren, J. Suttles, J. M. Davis, K. S. Buckley, S. Simandle, D. E. Butterworth, O. R. Fagoaga, S. L. Nehlsen-Cannarella. Departments of Health, Leisure, and Exercise Science; Biology; Appalachian State University, Boone, North Carolina 28608. Department of Biochemistry, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee 37614. Department of Exercise Science, School of Public Health, University of South Carolina, Columbia, South Carolina 29208.Immunology Center, Loma Linda University Medical Center, Loma Linda, California 92350.
APStracts 2:0170A, 1995.
The effect of 2.5 hours of treadmill running at 75.6+/-0.9% VO2max on natural killer cell cytotoxic activity (NKCA) was investigated in 22 experienced marathon runners (VO2max 57.9+/-1.1 ml.kg-1.min-1, age 38.7+/-1.5 yrs). Blood samples were taken before (0715 h) and immediately after exercise (1000 h), with three more samples taken during 6 h of recovery (1130, 1300, 1600 h). Ten sedentary controls (34.7+/-1.0 ml.kg-1.min-1 , 45.3+/-2.3 yrs) sat in the laboratory during testing and had their blood sampled at the same time points. The pattern of change in NKCA over time was significantly different between groups [F(4,27)=6.53, P=0.001], with the runner's NKCA dropping 51-61% below pre-exercise levels throughout 6 h of recovery. Preincubation of blood mononuclear cells in vitro with indomethacin had no effect on the difference in pattern of change in NKCA between groups [F(4,17)=8.59, P=0.001], and did not attenuate the post -exercise reduction in the runners. When NKCA was adjusted on a per-NK cell basis, group differences and the post-exercise decline in NKCA were eliminated [F(4,80)=0.65,P=0.63]. Serum cortisol and plasma epinephrine in the runners were elevated relative to controls during recovery from exercise, but no significant correlation with changes in NK cells or NKCA was found. These data indicate that NKCA is decreased significantly during recovery from 2.5 h running due to a numerical redistribution of NK cells.

Received 21 November 1994; accepted in final form 18 April 1995.
APS Manuscript Number A1185-4.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on  2 May 1995.