Heterogenic response of the liver parenchyma to ethanol studied in the bivascularly perfused rat liver

Zonation of ethanol oxidation and metabolic effects along the hepatic acini were investigated in the bivascularly perfused liver of fed rats. Ethanol was infused into the hepatic artery in antegrade and retrograde perfusion. Inhibition of glycolysis by ethanol, expressed as micromol min(-1) (ml accessible cell space)(-1), was more pronounced in the retrograde mode; the retrograde/antegrade ratio was equal to 1.63 for an ethanol infusion rate of 37.5 micromol min(-1) g(-1). Stimulation of oxygen uptake by ethanol was more pronounced in the retrograde mode; the retrograde/antegrade ratio was equal to 1.77. Diminution of the citrate cycle caused by ethanol was more pronounced in the retrograde mode; the retrograde/antegrade ratio was equal to 1.46. Transformation of arterially infused ethanol into acetate was more pronounced in retrograde perfusion; the retrograde/antegrade ratio was equal to 1.63. The increments in glucose release (glycogenolysis) caused by ethanol in the antegrade and retrograde modes were similar. It was assumed that the changes caused by arterially infused ethanol in retrograde and antegrade perfusion closely reflect a significant part of the periportal parenchyma and an average over the whole liver parenchyma, respectively. Under such assumptions it can be concluded that, in the perfused liver from fed rats, four related parameters predominate in the periportal region: ethanol oxidation, glycolysis inhibition, oxygen uptake stimulation and citrate cycle inhibition. One of the main causes for this predominance could be the malate/aspartate shuttle, which operates more rapidly in the periportal area and is essential for NADH oxidation.