Impact of high-fat diet on serum adiponectin and leptin level in streptozotocin-induced diabetes mellitus type 2

Objectives : Alternations in adipokines secretion associated with obesity could play an important role in diet-induced diabetes. The aim of our study was to estimate the impact of high-fat diet on serum adiponectin and leptin levels in streptozotocin (STZ) induced type 2 diabetes mellitus (T2DM). Methods : The study included 40 adult male Wistar rats were divided into four groups: Standard food control group (C-Non-HF)(n=10), standard food STZ group (STZ-NonHF)(n=10), high-fat diet control group (C-HF)(n =10) and high-fat diet STZ group (STZ-HF)(n =10). C-NonHF and STZ-NonHF group was fed with regular chow, and other two groups were given high-fat diet for 5 weeks. Type 2 DM was induced by single intra-peritoneal STZ injection (60 mg/kg). All the rats were fasted for 12 hours; when blood samples were taken for the measurement of serum leptin and adiponectin level by ELISA. Results : Mean serum adiponectin level was significantly lower in STZ-HF (1.34±0.57 ng/mL) compared to STZ-NonHF (2.61±0.79 ng/mL), C-NonHF (3.13±0.74 ng/mL) and C-HF group (3.04±0.63 ng/mL) (p<0.01). Mean serum leptin level was significantly higher in STZ-HF (1792.0}1378.8 pg/mL) compared to STZ-NonHF (634.0}149.1 pg/mL), C-NonHF (671.5}164.0 pg/mL) and C-HF group (593.8}200.8 pg/mL) (p<0.05). In STZ-HF group, a significant positive correlation between leptin and glucose level was observed (r=0.71; p=0.048). Conclusion : Our study results show that high fat diet induces an increase in serum leptin and the decrease in adiponectin levels in STZ diabetic rats and suggests that high fat diet impairs glucose control by increasing leptin secretion. Key words: Diabetes mellitus, leptin, adiponectin, obesity