UPTAKE OF GALACTOSE, OUABAIN AND TAUROCHOLATE INTO CENTRILOBULAR AND PERIPORTAL ENRICHED HEPATOCYTE SUB-POPULATIONS

  • 1 January 1981
    • journal article
    • research article
    • Vol. 216  (3) , 634-639
Abstract
Rat hepatocytes were isolated by a collagenase perfusion technique with subsequent subfractionation on metrizamide gradients into subpopulations which were designated band I and band II and are enriched with centrilobular and periportal cells, respectively. Band I had a higher concentration of 5''-nucleotidase and band II a higher concentration of alcohol dehydrogenase. Pretreatment of rats with phenobarbital led to hgiher cytochrome P-450 in the band I (centrilobular enriched) as compared to the band II (periportal enriched) subpopulations of hepatocytes. The ascribed lobular origins are supported. The uptake of a single concentration of galactose, ouabain and taurocholate into each of the 2 subpopulations was investigated until the concentration within the hepatocytes no longer increased. No difference was found in the uptake of [14C]galactose (25 mM) between the 2 hepatocyte subpopulations. The uptake of [3H]ouabain (125 .mu.M) was greater in the centrilobular as compared to periportal enriched fraction of the hepatocytes. An even greater difference was found for the uptake of [3H]taurocholate (25 .mu.M). The kinetics of taurocholate uptake were subsequently investigated. The Km for eachsubpopulation was 21 .mu.M while the Vmax of the centrilobular enriched fraction was 2.03 and that of the periportal enriched fraction was 2.03 and that of the periportal enriched fraction was 1.57 nmol/min per mg of protein. There apparently is a difference in uptake into hepatocytes of centrilobular and periportal origin for ouabain and taurocholate, but not for galactose.