Influence of Prednisolone Treatment on Serum Bile Acid Concentrations in Cats

While corticosteroids affect bile acid metabolism in humans and dogs, their impact on serum bile acids in cats is unknown. Moreover, the early effects of corticosteroids on liver enzyme activity in cats are not well understood. We prospectively studied seven healthy cats (4-7 years) treated with oral prednisolone (1.1-1.5 mg/kg, median 1.28 mg/kg PO daily) for 7 days. Serum bile acids and liver enzyme activities (ALT, AST, ALP, GGT) were measured before treatment (day 0) and at days 2, 3, 8, 10, and 14. Statistical analysis used the Friedman test with post hoc comparisons to baseline. At baseline, bile acids were within reference interval (1-6.5 μmol/L) (median 2.1 μmol/L, range 1-3.2) and increased significantly during treatment with prednisolone to a median of 5.3 μmol/L (range 1.8-8.7) at d8, but remained below clinically abnormal levels. In contrast, AST, ALT, and ALP activities decreased significantly during prednisolone administration. GGT activities were undetectable at all times. We conclude that, although prednisolone significantly affected bile acids, the effect is likely of limited clinical relevance, as increases were minimal and remained below thresholds considered abnormal. Unexpectedly, transaminase and alkaline phosphatase activities decreased in the first days after administration. The reasons for this remain unclear.