Alterations in serum concentrations of visfatin and betatrophin in dogs with hypothyroidism

Abstract

Background: Hypothyroidism in dogs is associated with obesity and altered lipid and carbohydrate metabolism. The adipokines, visfatin, and betatrophin, affect glucose tolerance. Betatrophin is involved in lipid regulation. Hypothesis: Visfatin and betatrophin serum concentrations are altered in hypothyroid dogs. Animals: Dogs with naturally occurring hypothyroidism (n = 25) and healthy dogs (n = 25). Methods: Insulin, visfatin, and betatrophin serum concentrations were measured in all dogs and 19 of the hypothyroid dogs after 30 days of thyroxine treatment. Body condition score (BCS) was determined (1-9 scale). Results: Visfatin concentrations were lower in hypothyroid compared with healthy dogs (mean, 95% confidence interval [CI]; 2.0 ng/mL, 1.2-3.3 vs 5.1 ng/mL, 3.3-7.8; P =.004) and increased post-treatment (3.1 ng/mL, 1.9-4.9 vs 2.6 ng/mL, 1.6-4.1; P =.05). Betatrophin concentrations were lower in lean to normal (body condition score [BCS], 3-5) hypothyroid dogs compared to lean to normal healthy dogs (52 pg/mL, 9-307 vs 597 pg/mL, 216-1648; P =.03), but were not different between overweight (BCS, 6-9) hypothyroid and healthy dogs (341 pg/L, 168-695 vs 178 pg/mL, 77-415; P =.26), and decreased post-treatment in overweight dogs (206 pg/mL, 87-488 vs 268 pg/mL, 112-640; P =.004). Visfatin concentrations were higher in overweight compared with lean to normal dogs (4.7 ng/mL, 3.3-6.6 vs 2.2 ng/mL, 1.2-4.2; P =.04). Betatrophin concentrations were positively correlated with BCS (r =.47, P =.02) and insulin concentrations (r =.48, P =.03) in hypothyroid dogs and negatively correlated with BCS (r = −.47, P =.02) and thyroid stimulating hormone concentrations (r = −.56, P =.01) in healthy dogs. Conclusions and Clinical Importance: Hypothyroidism in dogs is associated with alterations in visfatin and betatrophin concentrations that partially resolve with thyroxine treatment.