Inhibition of the prostaglandin synthetase systems in ocular tissues by indomethacin.

1 We have compared the sensitivity of the prostaglandin synthetase systems derived from microsomal fractions of rabbit ocular tissues (anterior uvea, conjunctiva and retina) with other rabbit tissues such as the kidney medulla and spleen, to inhibition by indomethacin.2 Generation of prostaglandin-like activity by the microsomal fractions from added arachidonic acid varied with the tissue used. Highest activity was found in the kidney medulla, then in descending order, the conjunctiva, anterior uvea, spleen, retina and cornea.3 Indomethacin was most potent in the spleen (ID(50) 0.045 mug/ml) then in decreasing order in the kidney medulla, conjunctiva, anterior uvea and weakest in the retina, where the ID(50) for indomethacin was 50 mug/ml.4 The differential sensitivity to inhibition of the prostaglandin synthetase systems from different tissues is an important consideration in the development of new ocular anti-inflammatory agents.