Bile pigments in gallbladder and freshly-secreted hepatic duct bile from fed and fasted rainbow trout, Oncorhynchus mykiss.

1. Chromatographic analyses of bile pigments in rainbow trout reveal the presence of primarily unconjugated biliverdin (BV) and bilirubin (BR) glycosyl conjugates. Only trace amounts of unconjugated BR are present in hepatic duct (HD) bile: no beta-glucuronidase activity is detectable. 2. The per cent of BV and BR in HD and gallbladder biles is similar in fasted trout; however, the per cent of BV is significantly increased in HD bile from fed fish. 3. Fasting decreases the rate of choleresis but does not alter the excretory rate of endogenous BV or BR. 4. Erythrocyte life span is estimated to be approximately 500 days.