Selective inhibition of thromboxane B2 accumulation and metabolism in perfused guinea-pig lung.

1 U46619, a prostaglandin H2 endoperoxide analogue and thromboxane A2 agonist, dose-dependently inhibited accumulation and metabolism of thromboxane B2 in the isolated perfused lung of the guinea-pig. At similar doses prostaglandins E1, E2, F1 alpha, F2 alpha, I2, 5, 6-trans-PGE2 and 8-iso-PGE1 were ineffective. 2 U46619 did not affect accumulation and metabolism of prostaglandin F2 alpha under similar conditions. 3 The pulmonary disposition of thromboxane B2, which occurs by uptake into pulmonary cells or binding to a specific macromolecular component, is mediated by a mechanism distinct from that handling prostaglandin F2 alpha. The possible relevance of these findings to the pulmonary disposition of thromboxane A2 is discussed.