Tromboxane B2 inhibits the pulmonary inactivation of prostaglandin E2 in the dog.

1 The systemic vasodepressor response to intravenously administered prostaglandin E2 (PGE2, 0.3, 1.0 and 3.0 micrograms/kg) is potentiated during intravenous infusion of thromboxane B2 (TXB2, 1.0 micrograms kg-1 min-1) in the anaesthetized dog. 2 The augmented haemodynamic response returns toward control values following cessation of the TXB2 infusion. 3 The systemic haemodynamic responses to intra-arterially administered PGE2, PGF2 alpha and PGI2 as well as intravenously administered PGF2 alpha and PGI2 are not altered by TXB2 infusion. 4. This study suggests that TXB2 inhibits the pulmonary inactivation of PGE2. 5 Arachidonic acid metabolites may interact, producing haemodynamic responses differing from their individual effects.