Modification of prostaglandin and thromboxane release by immunological sensitisation and successive immunological challenges from guinea-pig lumg.

The release of prostaglandins (PGs) and thromboxanes (Txs) from perfused guinea pig lungs was investigated during different immunological states. The major product released from normal lungs perfused with exogenous arachidonic acid was 6-oxo-PGF1a. The procedure of sensitisation to specific antigen resulted in an increase in the release of 15-oxo-13,14-dihydro-TxB2 and a decrease in the release of 6-oxo-PGF1a- and 6,15-dioxo-13,14-dihydro-PGF1a from lungs perfused with arachidonic acid. The relative amount of 15-oxo-13,14-dihydro-TxB2 released progressively increased with the number of immunological challenges with both exogenous and endogenously derived substrate, arachidonic acid. This change in response to successive immunological challenges may represent a protective mechanism to prevent parent Txs and PGs entering the systemic circulation.