Quantities of prostaglandin E2 (PGE2) in carrageenin-induced inflammatory exudate at the rat hind paw were measured by the radioimmunoassay method. PGE2 level increased rapidly and peaked 3 hours after treatment of carrageenin. Intravenous administration of LM-001, indomethacin (IM) and aspirin DL-lysine (VP), given 1 hour after treatment of carrageenin, significantly lowered the PGE2 level in the exudate (sampled 3 hours after treatment of carrageenin), dose-dependently. ID50 value (95% confidence limits) of each drug was as follows; LM-001: 1.2 (0.2-6.5) mg/kg, VP: 26.9 (4.5-161.2) mg/kg and IM: 0.2 mg/kg (95% confidence limit was impossible to be calculated) . These drugs very significantly reduced the PGE2 concentration in exudate, but the edema formation was not always suppressed to the same degree of PGE2 biosynthesis. These findings suggest that antiinflammatory potencies of these drugs are unable to account for only the inhibitory potencies of PGE2 biosynthesis in this model.
