Cyclooxygenase (COX) is the enzyme that catalyzes the rate-limiting step in prostaglandin (PG) synthesis. In skeletal muscle, PGF2a, has been shown to regulate protein synthesis, and ibuprofen and acetaminophen have been shown to block the normal increase in PGF2a and muscle protein synthesis following resistance exercise in humans. The purpose of this investigation was to determine the expression of the COX-1 (COX-1 variants: COX-1 v1, -1v2, -1 b,, -1 b2, and -1b3) and COX-2 isoforms following resistance exercise to help elucidate the isoform or variant through which PGF2a, ibuprofen, and acetaminophen regulate muscle protein synthesis. Human skeletal muscle biopsy samples were taken from 16 individuals (8M, 8F) before, 4 h, and 24 h following a single bout of resistance exercise and analyzed using real-time RT-PCR. COX-Iv1 and COX-1v2 were the most abundant COX mRNA before exercise and remained unchanged (P>0.05) following exercise (i.e., constitutively expressed). Relatively few individuals expressed the intron 1-retaining COX-1 b variants (COX-1 b,, - 1b2, and -1 b3) at any time point, and when expressed these variants were in very low abundance. COX-2 was not expressed in any subject before exercise, but increased significantly (P<0.05) at 4 and 24 h following exercise. These results suggest that the intron 1-retaining COX-1 b,, -1 b2, and -lb3 variants are likely not the COX through which PGF2a is produced to stimulate skeletal muscle protein synthesis. PGF2a, stimulation, as well as ibuprofen and acetaminophen inhibition of skeletal muscle protein synthesis likely work through COX-2, or one of the constitutively expressed COX-1 variants (COX-lv1 or -1v2). / School of Physical Education, Sport, and Exercise Science
| Identifer | oai:union.ndltd.org:BSU/oai:cardinalscholar.bsu.edu:handle/188202 |
| Date | January 2006 |
| Creators | Weinheimer, Eileen M. |
| Contributors | Trappe, Todd A. |
| Source Sets | Ball State University |
| Detected Language | English |
| Format | vii, 83 leaves : ill. (some col.) ; 28 cm. |
| Source | Virtual Press |
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