Effect of trilostane on serum concentrations of aldosterone, cortisol, and potassium in dogs with pituitary-dependent hyperadrenocorticism.

OBJECTIVE

To evaluate the effect of trilostane on serum concentrations of aldosterone, cortisol, and potassium in dogs with pituitary-dependent hyperadrenocorticism (PDH), compare the degree of reduction of aldosterone with that of cortisol, and compare aldosterone concentrations of healthy dogs with those of dogs with PDH.

METHODS

17 dogs with PDH and 12 healthy dogs.

METHODS

For dogs with PDH, the initial dose of trilostane was selected in accordance with body weight. A CBC count, serum biochemical analyses, and ACTH stimulation tests were performed in each dog. Dogs were evaluated 1, 3 to 4, 6 to 8, and 10 to 12 weeks after initiation of treatment. Healthy dogs were evaluated only once.

RESULTS

Serum aldosterone concentrations before ACTH stimulation did not change significantly after initiation of treatment with trilostane. At each evaluation after initiation of treatment, serum aldosterone concentrations after ACTH stimulation were significantly lower than corresponding concentrations before initiation of treatment. The overall effect of trilostane on serum aldosterone concentration was less pronounced than the effect on serum cortisol concentration. Median potassium concentrations increased slightly after initiation of treatment with trilostane. Dogs with PDH had significantly higher serum aldo sterone concentrations before and after ACTH stimulation than healthy dogs.

CONCLUSIONS

Treatment with trilostane resulted in a reduction in serum cortisol and aldosterone concentrations in dogs with PDH, although the decrease for serum aldosterone concentration was smaller than that for serum cortisol concentration. There was no correlation between serum concentrations of aldosterone and potassium during treatment.