Skeletal muscle PGF(2 alpha) and PGE(2) in response to eccentric resistance exercise: Influence of ibuprofen and acetaminophen

PGs have been shown to modulate skeletal muscle protein metabolism as well as inflammation and pain. In nonskeletal muscle tissues, the over the count er analgesic drugs ibuprofen and acetaminophen function through suppression of PG synthesis. We previously reported that ibuprofen and acetaminophen i nhibit the normal increase in skeletal muscle protein synthesis after high intensity eccentric resistance exercise. The current study examined skeleta l muscle PG levels in the same subjects to further investigate the mechanis ms of action of these drugs in exercised skeletal muscle. Twenty-four males (25 +/- 3 yr) were assigned to 3 groups that received the maximal over the counter dose of ibuprofen (1200 mg/d), acetaminophen (4000 mg/d), or a pla cebo after 10-14 sets of 10 eccentric repetitions at 120% of concentric 1 r epetition maximum using the knee extensors. Preexercise and 24 h postexerci se biopsies of the vastus lateralis revealed that the exercise-induced chan ge in PGF(2 alpha) in the placebo group (77%) was significantly different ( P < 0.05) from those in the ibuprofen (-1%) and acetaminophen (-14%) groups . However, the exercise-induced change in PGE, in the placebo group (64%) w as only significantly different (P < 0.05) from that in the acetaminophen g roup (-16%). The exercise-induced changes in PGF(2 alpha) and PGE(2) were n ot different between the ibuprofen and acetaminophen groups. These results suggest that ibuprofen and acetaminophen have a comparable effect on suppre ssing the normal increase in PGF(2 alpha) in human skeletal muscle after ec centric resistance exercise, which may profoundly influence the anabolic re sponse of muscle to this form of exercise.