EFFECTS OF VOLUME LOADING ON THE ATRIAL-NATRIURETIC-FACTOR AND THE RENIN-ALDOSTERONE SYSTEM IN EXPERIMENTAL LIVER-CIRRHOSIS

Serum concentrations of ANF, Renin and Aldosterone were measured in animals with experimental cirrhosis and volume overload. We studied 75 Wistar rats divided in five groups. Group I: rats with hepatic cirrhosis induced by CCl4; Group II: Control rats; Group III: rats with hepatic cirrhosis and continuous infusion of saline serum; Group IV: control rats with continuous infusion and Group V: cirrhotic rats and bolus infusion of saline. There were no statistical differences in serum concentrations of ANF (232+/-75 vs 195+/-42 pg/ml) and Renin concentration (182+/-24 vs 171+/-34 ng/ml/hora) between controls and rats with cirrhosis. However, Aldosterone levels were elevated in cirrhotic rats in basal conditions as compared to controls (1197+/-287 vs 475+/-88 pg/ml; p<0.001). The volume overload caused a paradoxical decrease of ANF in cirrhotic rats (124+/-15 and 122+/-17; p<0.001). On the other hand, no changes were observed in Renin and Aldosterone after volume expansion. These results suggest the existence of a hemodynamic response to compensate the volume overload. Other studies are necessary to confirm this hypotesis.