Serum leptin, adiponectin and tumor necrosis factor-α in hyperlipidemic rats with/without concomitant diabetes mellitus.

We compared the lipid profiles and serum levels of leptin, adiponectin and tumor necrosis factor-α (TNF-α) in rats with/without hyperlipidemia and with/without concomitant diabetes mellitus. Forty 10-wk-old male Wistar rats were divided into four groups. Groups A and C received standard food for 12 wks. Groups B and D received a high-fat diet enriched with 2% additional cholesterol. Moreover, insulin-deficient (type I) diabetes mellitus was induced in rats in groups C and D with intraperitoneal injections of streptozotocin. Fasting serum leptin levels were decreased in diabetic groups (groups C and D) compared with controls. Fasting serum adiponectin levels were decreased in groups C and D compared with group A. Serum TNF-α levels were augmented in groups B and D, those fed with an atherogenic diet. By contrast, TNF-α levels were decreased in group C. Our data suggest that serum leptin, adiponectin and TNF-α levels may serve as markers of obesity and type I diabetes mellitus.