Lien et al. Acta Veterinaria Scandinavica 2010, 52:61 http://www.actavetscand.com/content/52/1/61 Microalbuminuria is defined as the presence of a small amount of albumin (1 to 30 mg/dL) in the urine [16]. Microalbuminuria assays are more sensitive to albumin loss in the urine than the common urine dipstick, and urinary protein:creatinine ratio tests can detect protein loss through the urine with lower limits-of-detection than urine dipsticks. Microalbuminuria is used as an indicator in screening for early-stage renal and cardio- vascular diseases in humans [12,14,17,20,21]. It is a well-known risk factor associated with deteriorated car- diovascular mortality and diabetic nephropathy in human beings [12-14,17]. Similarly, microalbuminuria is associated with renal and systemic sub-clinical diseases in dogs and cats [22-24]. The purposes of this study were to report the relation- ship between ACTH-stimulation tests, systemic blood pressure, microalbuminuria and albuminuria in dogs affected with naturally occurring pituitary-dependent (PDH) and adrenal-dependent hyperadrenocorticism (ADH). Methods Animals Informed consent was obtained from all dog owners prior to the study, and number of animals of each breed in each group are shown in Table 1. Clinically healthy dogs One hundred clinically healthy client-owned dogs visit- ing the National Taiwan University Veterinary Hospital from 2005 to 2009 for routine health checkups and/or annual vaccination were included in this study. Of the clinically healthy dogs, 29 were intact females, 19 were spayed females, 45 were intact males, and 7 were castrated males. The average age was 5.1 ± 3.5 years (range 0.9 to 15 years), and average body weight was 11.6 ± 9.1 kg (range 1.8 to 35.0 kg). Thorough physical examination, blood pressure measurements and routine blood work (complete blood counts and biochemical profiles) were performed to exclude heart and renal dis- orders that might affect blood pressure or cause micro- albuminuria or albuminuria. Dogs affected with hyperadrenocorticism Medical records of 278 dogs in the National Taiwan University Veterinary Hospital during 2005-2009 with clinical signs of HAC and results of ACTH stimulation tests consistent with hyperadrenocorticism were screened. Only 70 of these records included conclusive results from an ACTH stimulation test, ultrasonographic evidence of adrenal glands, blood pressure measure- ments and microalbuminuria analysis. Therefore, only 70 dogs were included in the study. Inclusion criteria of HAC were clinical signs consis- tent with a diagnosis of HAC (e.g., polydipsia, polyuria, polyphagia, decreased activity, panting, a potbellied Page 2 of 6 ADH 1 1 0 0 1 1 0 0 9 1 1 2 2 0 0 3 0 0 0 5 1 0 2 30 Table 1 Breeds and numbers of the 100 clinical healthy dogs, 40 dogs affected with pituitary-dependent hyperadrenocorticism (PDH) and 30 dogs affected with adrenal-dependent hyperadrenocorticism (ADH) appearance, and dermatologic problems), results of rou- tine serum biochemical analyses that were consistent with a diagnosis of HAC (i.e., elevated activities of hepa- tic enzymes), and affirmative results of adrenocorticotro- pic hormone (ACTH) stimulation tests (post-ACTH cortisol concentration >20 μg/dL) [25]. Dogs with inconclusive results of ACTH stimulation tests were excluded from the study. Further differentiation between PDH or ADH was based upon adrenal ultrasonographic findings [1,26,27]. Size, shape, presence of nodular appearance and hyperechoic foci: normal or mild enlarged adrenal glands were classified as PDH; whereas adrenal glands with a nodular (or mass) appearance and hyperechoic foci were classified as ADH [1,26,27]. All included dogs were required to have had an ACTH stimulation test with intramuscular injection of 0.25 mg synthetic ACTH (Cortrosyn, Organon, The Netherlands). Informed consent was obtained from all owners prior to diagnostic testing. Blood samples for serum cortisol measurements were collected via cephalic venipuncture immediately before, and 1 hour after syn- thetic ACTH was injected. Serum cortisol concentra- tions were measured by a validated radioimmunoassay Breed Akita inu Beagle Bichon frise Chihuahua Cocker Spaniel Japanese spitz Golden retriever Lhasa apso Maltese terrier Miniature pinscher Miniature poodle Miniature schnauzer Mixed breed Papillon Pekingese Pomeranian Pug Shetland sheep dog Shihba inu Shih Tzu Short-haired dachshund West Highland white terrier Yorkshire Terrier Total Clinically Healthy 0 1 0 0 2 0 2 1 20 3 10 5 22 1 1 9 1 1 0 5 0 0 16 100 PDH 0 2 1 1 1 2 0 0 7 1 3 2 7 0 0 3 0 0 1 4 0 1 4 40