Interaction Between Aldosterone and Renomedullary Prostaglandins. Competitive Action Between Aspirin and Spironolactone

Aldosterone injected i.m. decreased the release of renomedullary PGEs and the index (urinary Na/K ratio) in conscious normotensive intact and adrenalectomized rats. Coadministration of spironolactone increased the release of PGEs as well as the index (urinary Na/K ratio). The effect of spironolactone was partly inhibited by aspirin injected in a ratio 5∶1 (aspirin: spironolactone), an effect which could be reversed by the infusion of a synthetic prostaglandin (PGA2) in a subhypotensive dose.