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.
Animals—17 dogs with PDH and 12 healthy dogs.
Procedure—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 and Clinical Relevance—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. (Am J Vet Res 2004;65:1245–1250)