ACUTE AND CHRONIC LOSARTAN ADMINISTRATION - EFFECT ON ANGIOTENSIN-II CONTENT AND MODULATION OF [H-3] NOREPINEPHRINE RELEASE FROM RAT INTERSCAPULAR BROWN ADIPOSE-TISSUE

To determine if acute or chronic (21 days) losartan (10 mg/kg, s.c.) r egulates the renin-angiotensin system in interscapular brown adipose t issue, angiotensin II (AII) content and [H-3]overflow from slices prel oaded with [H-3]norepinephrine were examined. Acute or chronic losarta n administration had no effect on AII content. AII increased evoked [H -3]overflow from slices from control rats. Losartan administration did not alter basal [H-3]outflow or evoked [H-3]overflow. Acute losartan administration inhibited AII-induced enhancement of evoked [H-3]overfl ow. Tolerance developed to the inhibitory effect of losartan following chronic administration.