Inhibition of biliary phospholipid secretion by bilirubin in partially hepatectomized rats

The effect of i.v. administration of bilirubin on biliary phospholipid secretion was studied in sham operated and two-thirds hepatectomized Wistar rats. Following bilirubin infusion at 260 nmol/100 g body wt/min, a maximal biliary bilirubin excretion was reached in the sham operated rats. No modifications of bile flow or bile acid secretion appeared, but biliary phospholipid secretion was significantly inhibited. At 12 and 24 h after hepatectomy, the maximal bilirubin excretion was markedly lowered but biliary phospholipid secretion still remained significantly inhibited. The infusion of taurocholate at 200 nmol/100 g body wt/min counteracted the impairment of phospholipid secretion, both in sham operated and hepatectomized animals. Bile acid secretions more than two-fold that of the controls were needed to reach half maximal biliary phospholipid secretion in bilirubin-infused animals, with or without the addition of taurocholate.