NATURAL KILLER CELL ACTIVITY FOLLOWING 6 WEEKS OF STRENGTH TRAINING IN HEALTHY YOUNG MALES WITH/WITHOUT TESTOSTERONE ENANTHATE ADMINISTRATION

There is limited information on the acute immune response to resistance-training programs in combination with short-term administration of the anabolic androgenic steroid, testosterone enanthate (TE), in healthy young males. Eighteen healthy young men were match-paired and randomly assigned in a double-blind manner to either a TE or a placebo (PG) group. All subjects performed a structured resistance-training program while receiving injection of either TE at the dosage of 3.5 mg per kilogram body mass, or saline as placebo, once weekly for 6 weeks. A 10-second all-out cycle sprint test was conducted at the beginning (Week 0) and end (Week 6) of the treatment period. NK, B and T lymphocyte populations were counted and natural killer cytotoxic activity (NKCA) was measured prior to and 5 minutes post the cycle sprint at Weeks 0 and 6. The TE group significantly increased their total work in the 10-second cycle sprint test from Week 0 to Week 6 (p< 0.04), while there was no significant increase for total work in the PG group. There was a significant increase in NKCA from Week 0 to Week 6 (p < 0.05) in the PG group. A significantly higher NKCA in the PG group than in the TE group was found in the post exercise sample in Week 6 (p<0.04). No significant differences were found between groups for the lymphocyte subsets. The 6-week strength training increased acute NKCA response to anaerobic type of exercise as shown in the PG group. Although dosing of TE enhanced anaerobic performance, the NKCA response in the TE group was lower than that in the PG group. The impact of this altered immune response on athletes' health requires further investigation. [J Exerc Sci Fit. Vol 6. No 2. 106-114. 2008]