QUANTITATIVE MODIFICATIONS INDUCED BY ANGIOTENSIN-II ON RAT BILE SECRETION

Angiotensin II (ANG II) effects on bile secretion were studied in the rat. ANG II (0.1 mu g/kg) was injected into the jugular vein every 30 min and bile samples of 30 min were collected for 120 min. Blood arter ial and portal venous pressures were simultaneously recorded before an d after the administration of ANG II. Results showed that ANG II decre ased bile now and the excretion of sodium, potassium, chloride and bil e acids whereas it increased pH, bile osmolality and the excretion rat e of bicarbonate and calcium. ANG II also led to a rapid increase in m ean arterial pressure as well as portal venous pressure which reverted to control values within 1 min. The present results suggest that ANG II may modulate bile flow and the excretion rate of the different bili ary constituents. We have previously investigated atrial natriuretic f actor effects on bile secretion and although the atrial factor antagon izes most of ANG II biological actions, unexpectedly, ANG II effects o n bile secretion were not opposite to those of atrial natriuretic pept ide. The modifications induced by ANG II on bile secretion may play an important role in pathophysiological conditions such as hypertensive states with increased ANG II circulating levels.