Three hours to 14 days following the intravitreal injection of 10 ng ofE. coliendotoxin into the vitreal chamber of one eye of the New Zealand white rabbit, ocular inflammation was evaluated by clinical and biochemical criteria and prostaglandins were measured in the intraocular fluids and in the incubation medium of the intact lens. Increased synthesis of PGE2 was detected for lenses from inflamed eyes beginning at 18 h post-endotoxin injection. Lenticular PGE2synthesis remained above control levels for the duration of the time course. Lenses also exhibited increased PGF2αsynthesis, which began at 18 h and returned to control levels by day 7. At the times of peak production, aqueous humor PGE2concentration correlated with lenticular PGE2synthesis and with aqueous humor leukocyte number. No correlations were found for lenticular PGE2vs. cell number, or vitreous humor PGE2vs. aqueous humor PGE2.These results suggest that during ocular inflammation, aqueous humor PGE2may be derived, at least in part, from the lens and leukocytes.