Thromboxane A2 antagonistic action of a new anti-ulcer agent, azuletil sodium (KT1-32).

The TXA2/PGH2 receptor antagonistic activity of azuletil sodium (KT1-32), a new anti-ulcer agent, was examined. KT1-32 competitively antagonized the contraction of canine gastric arteries induced by U-46619, PGF2 alpha, and PGE2, whereas it had no effect on the PGF2 alpha-, PGE2- and LTD4-induced contraction of guinea-pig ileum, which was not affected by U-46619. In anesthetized dogs, KT1-32 significantly reduced the U-46619-induced decrease in gastric arterial blood flow. Gastric contraction induced by U-46619 in anesthetized rats was markedly inhibited by KT1-32. KT1-32 showed no influence on TXA2 synthetase and cyclooxygenase activities. These results indicate that KT1-32 is a competitive TXA2/PGH2 receptor antagonist, which may be important as to the effectiveness of KT1-32 against gastric ulcer.