Effect of glucocorticoid administration on serum aldosterone concentration in clinically normal dogs.
OBJECTIVE
To evaluate the effects of oral administration of anti-inflammatory dosages of prednisone for 28 days on serum aldosterone, cortisol, and electrolyte concentrations in clinically normal dogs.


METHODS
10 dogs.


METHODS
On days 1 through 28, 5 dogs received prednisone (0.55 mg/kg, PO, q 12 h) and 5 dogs received similar treatments with a placebo (empty capsules). Serum cortisol and aldosterone concentrations before and after ACTH stimulation testing and serum electrolyte concentrations were measured before (day 0 [baseline]), during (days 7, 14, 21, and 28), and after (days 35 and 42) treatment.


RESULTS
At baseline, variables did not differ between the 2 groups. Serum cortisol concentrations before and after ACTH stimulation testing did not change from baseline values in placebo-treated dogs. In prednisone-treated dogs, serum chloride and corrected chloride concentrations were significantly lower on days 7, 14, 21, and 28 and serum bicarbonate concentrations were significantly higher on days 14, 21, and 28, compared with baseline values. Serum cortisol concentrations before and after ACTH stimulation testing were significantly lower than baseline values during prednisone treatment. Serum aldosterone concentration after ACTH stimulation testing was significantly lower than baseline on day 35 (ie, 1 week after discontinuation of prednisone treatment) but returned to baseline by day 42 in prednisone-treated dogs.


CONCLUSIONS
Administration of anti-inflammatory dosages of prednisone caused significant changes in serum chloride, bicarbonate, and cortisol concentrations in clinically normal dogs. Although ACTH-stimulated serum aldosterone concentrations were unchanged from baseline during glucocorticoid administration, values decreased after treatment cessation but quickly returned to baseline values.
Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA.
Anne M
AM
Corrigan
Ellen N
EN
Behrend
Linda G
LG
Martin
Robert J
RJ
Kemppainen
D000302:Adrenal Cortex / Q000187:drug effects / Q000378:metabolism; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000450:Aldosterone / Q000097:blood*; D000818:Animals; D001639:Bicarbonates / Q000097:blood; D002712:Chlorides / Q000097:blood; D004285:Dogs / Q000097:blood*; D005260:Female; D005938:Glucocorticoids / Q000494:pharmacology*; D006854:Hydrocortisone / Q000097:blood; D008297:Male; D009994:Osmolar Concentration; D011188:Potassium / Q000097:blood; D011241:Prednisone / Q000494:pharmacology*; D011897:Random Allocation; D012964:Sodium / Q000097:blood; D018709:Statistics, Nonparametric
D001639:Bicarbonates; D002712:Chlorides; D005938:Glucocorticoids; D000450:Aldosterone; D000324:Adrenocorticotropic Hormone; D012964:Sodium; D011188:Potassium; D011241:Prednisone; D006854:Hydrocortisone