title: Aldosterone-to-renin and cortisol-to-adrenocorticotropic hormone ratios in healthy dogs and dogs with primary hypoadrenocorticism.
abstract: In dogs with primary hypoadrenocorticism, hypocortisolism and hypoaldosteronism usually are present, but these deficiencies also may occur in isolated forms. The diagnosis is commonly made by measuring plasma cortisol concentration before and after stimulation with ACTH, thereby ignoring aldosterone. In search of an alternative approach that would include assessment of glucocorticoid and mineralocorticoid production, 2 pairs of endocrine variables were measured: (1) plasma concentration of cortisol and ACTH, and (2) plasma aldosterone concentration and plasma renin activity. In addition, the cortisol-to-ACTH ratio (CAR) and the aldosterone-to-renin ratio (ARR) were calculated. Reference intervals were established in a population of 60 healthy dogs. In these dogs, CAR ranged from 1.1 to 26.1 and ARR ranged from 0.1 to 1.5. The variables were compared with those of 22 dogs with spontaneous primary hypoadrenocorticism. Plasma concentration of cortisol and ACTH in both groups of dogs overlapped, whereas CAR did not. Similarly, plasma aldosterone concentration and plasma renin activity overlapped, whereas ARR did not. These observations indicate that measurement of these endogenous variables (in one blood sample) allows the specific diagnoses of primary hypocortisolism and primary hypoaldosteronism.
authors.affiliation: Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, The Netherlands.
authors.forename: Shahram
authors.initials: S
authors.lastname: Javadi
authors.forename: Sara
authors.initials: S
authors.lastname: Galac
authors.forename: Peter
authors.initials: P
authors.lastname: Boer
authors.forename: Joris H
authors.initials: JH
authors.lastname: Robben
authors.forename: Erik
authors.initials: E
authors.lastname: Teske
authors.forename: Hans S
authors.initials: HS
authors.lastname: Kooistra
mesh_terms: D000309:Adrenal Insufficiency / Q000175:diagnosis / Q000662:veterinary*; D000324:Adrenocorticotropic Hormone / Q000097:blood; D000450:Aldosterone / Q000097:blood; D000818:Animals; D001774:Blood Chemical Analysis / Q000662:veterinary; D004283:Dog Diseases / Q000097:blood / Q000175:diagnosis*; D004285:Dogs / Q000097:blood*; D005260:Female; D006854:Hydrocortisone / Q000097:blood; D008297:Male; D010912:Pituitary-Adrenal Function Tests / Q000662:veterinary; D011237:Predictive Value of Tests; D012083:Renin / Q000097:blood
chemical_list: D000450:Aldosterone; D000324:Adrenocorticotropic Hormone; D012083:Renin; D006854:Hydrocortisone