Summary
Disposition kinetics of indocyanine green (icg) were used to evaluate hepatic function in healthy Beagles (group 1; n = 6) and Beagles with progressive hepatic disease induced by oral administration of dimethylnitrosamine, a hepatospecific toxin. Three classes of hepatic disease were defined by histologic features: mild (group 2; n = 5), moderate (group 3; n = 6), and severe (group 4; n = 5). Disposition of icg was studied 3 weeks following the last dose of toxin. A rapid iv injection of 0.5 mg of icg/kg was administered and serum samples were obtained at certain intervals during 60-minute periods. Serum icg was analyzed by use of visible spectrophotometry. Disposition kinetics were determined from serum icg concentrations vs 15- and 60-minute time curves and compared between one another and among groups. Data based on 60-minute time curves were not significantly different from those based on 15-minute curves. Area under the curve for icg was greatest in group 3. Clearance of icg was decreased and mean resident time was increased in groups 3 and 4, compared with those in groups 1 and 2. When disposition data (60 minutes) were normalized for differences in hepatic weight among dogs, group-3 mean resident time was significantly greater than that of group 4. This study supports the diagnostic benefits of using icg disposition kinetics as a method of evaluating hepatic function in dogs with progressive liver disease.
