Serum Adipokine Concentrations in Dogs with Naturally Occurring Pituitary-Dependent Hyperadrenocorticism

Background An excess of intra-abdominal fat is observed frequently in dogs with hyperadrenocorticism (HAC). Adipokine dysregulation is a possible cause of complications related to visceral obesity, but little information is available on adipokine in dogs with naturally occurring HAC. Objectives To examine the differences in the circulating adipokines concentrations in overweight dogs with and without pituitary-dependent HAC (PDH). Animals Thirty healthy dogs and 15 client-owned dogs with PDH. Methods Case-controlled observational study, which enrolled 15 overweight dogs diagnosed with PDH and 30 otherwise healthy dogs of similar body condition score. Nine of 15 dogs with PDH were treated with low-dose trilostane twice daily and reassessed after treatment. Results The serum leptin (P<.0001) and insulin (P<.0001) concentrations were significantly higher in the PDH group (leptin, 22.8 +/- 8.8 [mean +/- SD]; insulin, 9.1 +/- 6.1) than the healthy group (leptin, 4.9 +/- 3.7; insulin, 1.9 +/- 0.9). However, there were no significant differences in the adiponectin, resistin, tumor necrosis factor (TNF)-alpha, interleukin (IL)-1 beta, IL-6, IL-10, and IL-18 levels between the 2 groups. In the PDH group, the serum cortisol concentrations had a linear association with the leptin concentrations, and there were significant decreases in the leptin (P=.0039) and insulin (P=.0039) levels after trilostane treatment. However, the leptin and insulin levels remained higher after trilostane treatment than in healthy control dogs with similar body condition score. Conclusions and Clinical Importance Hypercortisolemia in dogs with PDH might upregulate the circulating leptin levels. However, a large population-based study will be necessary to determine whether the upregulation of leptin is involved directly with the complications caused by HAC.