The multiple-indicator dilution technique for characterization of normal and retrograde flow in once-through rat liver perfusions

Authors

  • Marie V. St-Pierre,

    1. Faculty of Pharmacy and Department of Pharmacology, Faculty of Medicine, University of Toronto, Toronto, Ontario, and McGill University Medical Clinic, Montreal General Hospital, Montreal, Quebec, Canada
    Search for more papers by this author
  • Andreas J. Schwab,

    1. Faculty of Pharmacy and Department of Pharmacology, Faculty of Medicine, University of Toronto, Toronto, Ontario, and McGill University Medical Clinic, Montreal General Hospital, Montreal, Quebec, Canada
    Search for more papers by this author
  • Carl A. Goresky,

    1. Faculty of Pharmacy and Department of Pharmacology, Faculty of Medicine, University of Toronto, Toronto, Ontario, and McGill University Medical Clinic, Montreal General Hospital, Montreal, Quebec, Canada
    Search for more papers by this author
  • Wai-Fong Lee,

    1. Faculty of Pharmacy and Department of Pharmacology, Faculty of Medicine, University of Toronto, Toronto, Ontario, and McGill University Medical Clinic, Montreal General Hospital, Montreal, Quebec, Canada
    Search for more papers by this author
  • K. Sandy Pang Ph.D.

    Corresponding author
    1. Faculty of Pharmacy and Department of Pharmacology, Faculty of Medicine, University of Toronto, Toronto, Ontario, and McGill University Medical Clinic, Montreal General Hospital, Montreal, Quebec, Canada
    • Faculty of Pharmacy, University of Toronto, 19 Russell St., Toronto, Ontario, Canada M5S 2S2
    Search for more papers by this author

  • This work was presented in part at the Annual Meeting of the American Association for the Study of Liver Diseases, Chicago, 1987, and was published in part as an abstract (Hepatology 1987; 7:1129)

Abstract

The technique of normal and retrograde rat liver perfusion has been widely used to probe zonal differences in drug-metabolizing activities. The validity of this approach mandates the same tissue spaces being accessed by substrates during both normal and retrograde perfusions. Using the multiple-indicator dilution technique, we presently examine the extent to which retrograde perfusion alters the spaces accessible to noneliminated references. A bolus does of 51Cr-labeled red blood cells, 125I-albumin, 14C-sucrose and 3H2O was injected into the portal (normal) or hepatic (retrograde) vein of rat livers perfused at 10 ml per min per liver. The outflow perfusate was serially collected over 220 sec to characterize the transit times and the distribution spaces of the labels. During retrograde perfusion, red blood cells, albumin and sucrose profiles peaked later and lower than during normal perfusion, whereas the water curves were similar. The transit times of red blood cells, albumin and sucrose were longer (p<0.005), whereas those for water did not change. Consequently, retrograde flow resulted in significantly larger sinusoidal blood volumes (45%), albumin Disse space (42%) and sucrose Disse space (25%) than during normal flow, whereas the distribution spaces for total and intracellular water remained unaltered. The distension of the vascular tree was confirmed by electron microscopy, by which occasional isolated foci of widened intercellular recesses and spaces of Disse were observed. Cellular ultrastructure was otherwise unchanged, and there was no difference found between normal and retrograde perfusion for bile flow rates, AST release, perfusion pressure, oxygen consumption and metabolic removal of ethanol, a substrate with flow-limited distribution, which equilibrates rapidly with cell water (hepatic extraction ratios were virtually identical: normal vs. retrograde, 0.50 vs. 0.48 at 6 to 7.4 mM input concentration). These findings suggest that the functional and metabolic capacities of the liver remain unperturbed during retrograde perfusion, rendering the technique suitable for the investigation of zonal differences in drug-metabolizing enzymes.

Ancillary