Indomethacin reduces the level of PGE₂in mouse serum. Serum PGE₂ measurement from serum of mice treated with and without indomethacin in their drinking water as described in “Materials and methods." Each circle represents the concentration of PGE₂ (pg/mL) in the serum from 1 mouse. Horizontal lines represent the mean of each treatment group, *P < .01 (unpaired Student t test).