Differential effects of diuretics on eicosanoid biosynthesis

The selective influences of hydrochlorothiazide (HCT), furosemide (FUR), spironolactone (SPI) and indapamide (IND) on arachidonic acid (AA) metabolism were assessed in sheep seminal vesicle and in human platelet microsomes. All four compounds augmented the synthesis of prostaglandins (PGs) D2 (HCT,FUR), E2 (SPI) and I2 (FUR,IND), probably through facilitated reorientation of endoperoxide biotransformation. With the exception of HCT, the other drugs also suppressed the production of thromboxane A2 (IND greater than SPI greater than FUR); lipoxygenase formation of hydroxyeicosatetraenoic acid was also enhanced by SPI and IND. The antihypertensive efficacy of these diuretics could, in part, be related to their selective effects on AA metabolism which favor the net formation of depressor PGs.