Comparison of leukotrienes as conjunctival microvascular permeability factors.

The effect of leukotrienes (LT) B4, C4, D4 and E4 on the microvascular permeability of the palpebral conjunctiva was investigated in the hamster. Microvascular permeability was quantitatively measured as extravascular albumin content by a technique which employs radiolabeled serum albumin and red blood cells. The natural 5S, 6R-LTD4 stereoisomer approached 1,000 times the potency of 5R, 6S-LTD4, indicating a stereoselective response to LTD4. 5S, 6R-LTD4 was approximately 100 times more active than LTC4, and LTE4 appeared no more active than 5R, 6S-LTD4. LTB4 was essentially inactive over a dose-range of 5-500 ng. These results indicate that the conjunctival microvasculature may vary markedly in terms of vasopermeability response to different LTs.