Serum adipokine concentrations in dogs with naturally occurring pituitary-dependent hyperadrenocorticism

Abstract

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)-α, interleukin (IL)-1β, 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.

Keywords: Adiponectin; Canine; Cortisol; Cushing's disease; Leptin.

Figure 1

Scatter plots of the serum leptin, adiponectin, resistin, insulin, and cortisol concentrations in healthy dogs (n = 30) and dogs with pituitary‐dependent hyperadrenocorticism (n = 15). The horizontal bars indicate the mean ± SD. *The mean values were significantly (P < .05) different in the 2 groups (unpaired t‐test).

Figure 2

Linear association between the serum cortisol and leptin concentrations in dogs with pituitary‐dependent hyperadrenocorticism. The dotted line indicates the 95% confidence intervals.

Figure 3

Scatter plots of the serum leptin, adiponectin, resistin, insulin, and cortisol concentrations in healthy dogs (n = 30) and dogs with pituitary‐dependent hyperadrenocorticism (PDH) (n = 9) before and after treatment with trilostane. The horizontal bars indicate the medians and ranges. *The values were significantly (P < .05) different within the PDH group (Wilcoxon matched‐pairs signed rank test).