Bile flow and biliary excretion rate of some organic anions in phenobarbital-pretreated rats.

Bile flow and the biliary excretion of indocyanine green, bromcresol green, eosine, bromsulphthalein-glutathione conjugate (BSP-GSH), amaranth and iodoxamic acid were investigated in control and phenobarbital-pretreated rats (75 mg/kg i.p. daily for 5 days). The bile flow was increased by phenobarbital from an average of 50.6 to 77.7 microliter/kg/min. Depending on the dose, the biliary excretion rate of bromcresol green was increased by 48-496% and that of eosine by 30-149%. After phenobarbital pretreatment the excretion of BSP-GSH was also enhanced by 34-52%, that of amaranth by 37-53% and that of iodoxamic acid by 40-56%. However, the biliary excretion of indocyanine green remained unchanged. There was no parallelism between the increase in bile flow and biliary excretion of the drugs.