RATES OF ALCOHOL DEHYDROGENASE-DEPENDENT ETHANOL-METABOLISM IN PERIPORTAL AND PERICENTRAL REGIONS OF THE PERFUSED-RAT-LIVER

  • 1 January 1982
    • journal article
    • research article
    • Vol. 21  (2) , 438-443
Abstract
Infusion of ethanol into Hb-free perfused rat liver increased NADH fluorescence (366 .fwdarw. 450 nm) which was measured with a large-tip (2-mm) light guide placed on the surface of the liver. A linear correlation (r = 0.83) was observed between the increase in NADH fluorescence and rate of ethanol uptake at 0.05-2.0 mM. When a micro-light guide (tip diameter 170 .mu.m) was placed on periportal or pericentral regions of the liver surface, the maximal fluorescence increase due to ethanol (2 mM) was 31.2 .+-. 2.0 and 31.9 .+-. 1.7% in periportal and pericentral regions, respectively. The infusion of 4-methylpyrazole (80 .mu.M), an inhibitor of alcohol dehydrogenase, completely abolished the fluorescence increase in both regions, indicating that the changes were entirely attributable to perturbation of cofactor levels due to alcohol dehydrogenase-dependent ethanol metabolism. By using the correlation between the NADH fluorescence increase and rate of ethanol uptake, rates of ethanol metabolism in periportal and pericentral regions were calculated. Values for maximal ethanol uptake were identical. Half-maximal ethanol uptake was observed at 0.24 and 0.25 mM ethanol in periportal and pericentral regions, respectively. The rates of alcohol dehydrogenase-dependent ethanol metabolism were similar in both regions of the liver lobule.