EFFECT OF LOSARTAN, AN ANGIOTENSIN-II RECEPTOR ANTAGONIST, ON RESPONSE OF CORTISOL AND ALDOSTERONE TO ADRENOCORTICOTROPIC HORMONE

Many imidazole derivatives are shown to inhibit adrenal steroid biosyn thesis. The present study was undertaken to examine an effect of anoth er imidazole derivative, losartan (an angiotensin II receptor antagoni st), on responses of cortisol and aldosrerone to adrenocorticotrophic hormone (ACTH). Nine patients with essential hypertension were given p lacebo orally for 7 days and 50 mg of losartan for the next 9 days. Re sponses of serum cortisol and plasma aldosterone to intramuscular ACTH injection were determined before and at the end of the treatment with losartan. Serum cortisol and plasma aldosterone significantly increas ed after ACTH injection in both periods of treatment (placebo and losa rtan). The increments in these parameters during treatment with losart an were not significantly different from those during treatment with p lacebo. These results suggest that the inhibitory effect of losartan o n adrenal steroid biosynthesis is negligible.