Abstract:

The aim of this study is to determine and compare the effect of obesity or insulin deficiency on plasma adiponectin level and peripheral blood leukocyte (PBL) adiponectin receptor 1 and 2 (ADIPOR1 and -R2) expression in dogs. Obese and insulin deficient (ID) dogs demonstrated a significant reduction (60% lower) and significant increase (2x higher) in circulating adiponectin level, respectively, as compared to normal controls. PBL ADIPOR1 and -R2 mRNA expression was also significantly higher in obese (R1=333 mean fold higher, R2=64 mean fold higher) and ID dogs preinsulin treatment (R1 =48 mean fold higher, R2=16 mean fold higher) as compared to normal PBL. Insulin treatment reduced ADIPOR1 (3 mean fold higher) and -R2 (1.5 mean fold higher) expression back down closer to control PBL levels in ID animals. The upregulation of adiponectin receptor expression might reflect an increased need for adiponectin signaling; however, the increase may have a different implication between obese and ID dogs. This may be due to adiponectin's contradictory paradoxical dual role, having both anti-inflammatory and pro-inflammatory properties on peripheral leukocytes, especially on monocytes depending on the biological context and adiponectin isoform.