The enzyme activities of expressed COX-2 and mPGES-1 enzymes between early and late phase of LPS treatment were not different.

<p>The induced COX-2 and mPGES-1 enzymes were immunoprecipitated (IP, 2 hrs at 4°C) separately from equal amount of BMDM lysates at either 8 or 16 hrs of LPS treatment under the same experimental condition. The IP COX-2 or mPGES-1 enzyme concentrations were determined, and equal amount of IP COX-2 or mPGES-1 enzymes from each time point was used to determine their enzyme activity of PGE₂ production from their substrates (either arachidonic acid or PGH₂) <i>in vitro</i>. No significant difference in either COX-2 or mPGES-1 enzyme activity of PGE₂ production was detected between 8 and 16 hrs of LPS treatment (n = 3).