The effect of a cyclooxygenase-2 inhibitor on human mixed muscle protein synthesis after acute resistance exercise

No Thumbnail Available
Burd, Nicholas A.
Trappe, Todd A.
Issue Date
Thesis (M.S.)
School of Physical Education, Sport, and Exercise Science
Other Identifiers

We have previously shown that non-specific blockade of the cyclooxygenase (COX) enzymes in skeletal muscle eliminates the normal increase in muscle protein synthesis following resistance exercise. The current study tested the hypothesis that this COX-mediated increase in postexercise muscle protein synthesis is specifically regulated by the COX-2 isoform. Sixteen males (23 ± 1 yr, 177 ± 2 cm, 81.5 ± 3.4 kg) were randomly assigned to one of two groups that received three doses of either a specific COX-2 inhibitor (celecoxib; 200 mg per dose, 600 mg total) or a placebo during the 24 hours following a single bout of resistance exercise with the knee extensors. Skeletal muscle fractional synthesis rate (FSR) was measured at rest and 24 hours postexercise using a primed constant infusion of [2H5]phenylalanine coupled with muscle biopsies of the vastus lateralis. Mixed muscle FSR was increased following exercise to a greater extent (206%, P<0.05) in the COX-2 group (0.052 ± 0.014 %Ih) as compared with the placebo group (0.017 ± 0.007 %Ih). These results suggest that the specific inhibition of the COX-2 isoform in human skeletal muscle causes a compensatory response in muscle protein synthesis. These data also highlight the involvement of the cyclooxygenase pathways in the regulation of muscle protein synthesis following resistance exercise.