A preliminary evaluation of the circulating leptin/adiponectin ratio in dogs with pituitary-dependent hyperadrenocorticism and concurrent diabetes mellitus

Abstract

Leptin and adiponectin are thought to modulate insulin sensitivity and pancreatic beta-cell function, but there is limited information regarding the adipokine status of hyperglycemic dogs with hyperadrenocorticism. This study aimed to determine whether alterations in the leptin/adiponectin ratio, insulin sensitivity, and/or pancreatic beta-cell function are associated with diabetes mellitus (DM) in dogs with pituitary-dependent hyperadrenocorticism (PDH). A total of 48 client-owned dogs were included in this prospective observational study: 20 dogs with PDH (10 normoglycemic and 10 with DM), 15 dogs with DM, and 13 healthy dogs. The serum concentrations of leptin, adiponectin, resistin, interleukin (IL)-1 beta, IL-6, IL-10, IL-18, and tumor necrosis factor (TNF)-alpha were measured, and homeostatic model assessment indices (HOMAs) were calculated and compared among the groups. Serum leptin was significantly higher in PDH dogs with and without DM than in healthy and DM dogs, and it was lower in DM dogs than in PDH dogs without DM. Serum adiponectin was significantly lower in PDH dogs with DM than in healthy and PDH dogs, and it was significantly lower in DM dogs than in healthy dogs. Serum IL-10 was significantly higher in PDH dogs with DM than in healthy and PDH dogs without DM. The leptin/adiponectin ratio was significantly higher in PDH dogs with DM than in normoglycemic PDH dogs. Serum IL-6 concentrations were significantly higher in DM dogs than in healthy dogs. Serum IL-1 beta concentration was significantly higher in DM dogs than in healthy dogs and PDH dogs with DM and without DM. Serum TNF-alpha and IL-18 concentrations were not different among groups. The HOMA(beta-cell function) was significantly lower in PDH dogs with DM than in normoglycemic PDH dogs, while HOMA(insulin sensitivity) was significantly lower in PDH dogs with DM than in healthy dogs. These results suggest that adipokine dysregulation, a reduction in insulin sensitivity, and a further impairment in pancreatic beta-cell function might predispose PDH dogs to DM. Further longitudinal study will be necessary to confirm this result. (C) 2020 Elsevier Inc. All rights reserved.