Comparison of serum biochemical and hepatic functional alterations in dogs treated with corticosteroids and hepatic duct ligation

Abstract

SUMMARY Differentiation of increased serum alkaline phosphatase ( alp ) activity associated with nonhyperbiiirubinemic cholestasis in dogs from that which occurs after corticosteroid induction was attempted, using various hepatic diagnostic enzymes and hepatic function tests. Nonhyperbilrubbinemic cholestasis was created in 5 dogs by ligation of the right hepatic duct; 5 sham-operated dogs served as controls. Corticosteroid induction of alp was created in 5 dogs by 11 daily doses of 3 mg of dexamethasone phosphate/kg, given iv ; 5 sham-treated dogs served as controls. The period of evaluation was 12 days. Enzymes measured daily were alp , γ-glutamyltransferase (γGT), leucine aminopeptidase ( lap ), alanine aminotransferase ( alt ), and arginase ( arg ). Sulfobromophthalein ( bsp ) dye excretion, ammonia tolerance tests, test for serum bile acid concentrations, and electrophoresis for serum alp isoenzyme activity were done on days 1, 6, and 12. Serum alp , alt , and γGT activities increased significantly ( P < 0.05) in all dogs subjected to hepatic duct ligation and those treated with dexamethasone. The onsets of increased activity, rates of increase, maximal activity, and rates of decline varied among the enzymes and according to treatment. Neither hepatic duct ligation nor dexamethasone treatment caused significant changes in lap and arg activities. Dexamethasone-treated dogs had significantly higher ( P < 0.05) bsp retention on days 6 and 12. Ammonia tolerance test results were in usual limits in all dogs, Serum bile acid concentrations increased after both hepatic duct ligation and dexamethasone treatment; however, the increases were significantly different ( P < 0.05) from control values in dogs with hepatic duct ligation on days 6 and 12. Electrophoresis revealed an indistinct steroid-induced alp isoenzyme band in 1 dexamethasone-treated dog on day 12.