Regulation of canalicular bile formation by α-adrenergic action and by external ATP in the isolated perfused rat liver

Abstract

In isolated perfused rat liver, addition of adrenaline induced a complex response of bile flow including rapid, reversible stimulation ( 1 2 –2 min ), reversible inhibition (2–10 min), and prolonged stimulation. Both the reversible stimulation and the inhibition were mimicked by the α-sympathomimetic agonist phenylephrine but not by the β-agonist isoproterenol. The reversible stimulation was a very early effect being terminated prior to all other α-adrenergic responses of liver. External ATP considerably lowered bile flow while inducing release of glucose and lactate, inhibition of respiration, and a reversible efflux of Ca 2+. Variations of mannitol clearance parallel to those of bile flow indicate a canalicular origin of all changes.