Relationship between the anti-inflammatory and irritant properties of inflammatory exudate.

1. Using the rat paw oedema assay procedure a comparison was made between the anti-inflammatory and irritant properties of the inflammatory exudate obtained from polyester sponges implanted subcutaneously in adrenalectomized rats. Where necessary, comparison was also made with a known counter-irritant, carrageenin.2. A significant correlation between the anti-inflammatory and irritant properties of sponge exudate was observed when each parameter was determined in relation to dose. A similar result was obtained with carrageenin.3. A comparison of the two activities of sponge exudate samples harvested at various times following sponge implantation did not give a significant correlation although in each case significant anti-inflammatory activity was accompanied by marked irritation.4. Time-effect curves of the two activities of sponge exudate showed a significant correlation over the time period examined. However, no such correlation was obtained using carrageenin.5. Both activities of sponge exudate were retained following dialysis.6. These findings are discussed in relation to a counter-irritant mode of action for sponge exudate.