Acute and chronic losartan administration: effect on angiotensin II content and modulation of [³H]norepinephrine release from rat interscapular brown adipose tissue

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