Leptin and adiponectin

Serum glucose, TG, total cholesterol (TC), high-density lipoprotein cholesterol (HDLC), and low-density lipoprotein cholesterol (LDLC) levels were determined with commercial kits (Nanjing Jiancheng, China) based on the manufacturer’s instructions. Serum lipopolysaccharide (LPS), LPS-binding protein (LBP), and free fatty acids (FFA) (BioVision, USA), tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6) (eBioscience, USA), and leptin and adiponectin (R&D Systems, USA) were measured using a commercial enzyme-linked immunosorbent assay (ELISA) kit.

Plasma TC, HDL-cholesterol, and TG levels were analyzed using commercial enzymatic kits (Asan Pharmaceutical, Seoul, Korea). LDL-cholesterol was calculated by the Friedewald’s formula: LDL-cholesterol = TC − HDL-cholesterol − TG/5. Glucose oxidase-based kits (Asan Pharmaceutical) were used to determine FBG levels according to the manufacturer’s protocol. Enzyme-linked immunosorbent assay (ELISA) kits were used to determine leptin and adiponectin (R&D Systems, Minneapolis, MN, USA), insulin and C-peptide (Mercodia, Uppsala, Sweden), osteocalcin, ALP, CTX, and NTX (Cusabio Biotech, Wuhan, China), and estradiol (Biovision, Milpitas, CA, USA) levels in plasma according to the manufacturer’s protocol. HOMA-IR was calculated using the following equation [34 (link)]: HOMA-IR = Fasting plasma insulin (µU/mL) × Fasting blood glucose (mmol/L)/22.5.