Complete blood was mixed with EDTA-2Na (2mgml1) and aprotinin (500kIUml1) to determine the plasma levels of FGF21. antibody had no significant effects on daily food intake and body weight gain in individually housed KK mice. These findings suggest that FGFR2-IIIc upregulates the adiposity induced by social isolation in KKAymice, and that decreased manifestation and/or function of FGFR2c might be a compensatory response to enhanced adiposity. Inhibition of FGFR2-IIIc function might be a novel therapeutic approach to get obesity. == Introduction == Fibroblast growth factor 21 (FGF21) is usually an atypical member of the FGF family members that functions as an endocrine hormone to regulate glucose and lipid metabolism. 1, 2Although FGF21 is reportedly produced in multiple tissues including liver, skeletal muscle, brown and white adipose cells, 3circulating FGF21 is mainly derived from the liver and created during fasting and feeding. 4, 5FGF21 administration raises energy expenditure, insulin sensitivity and weight loss, and normalizes glucose and lipid levels in obese and insulin-resistant rodents. 1, 6, 7, 8 Circulating FGF21 levels, however , are elevated in obese rodents9, 10and humans11and the expression of -Kotho, FGF receptor (FGFR)-1c and 2c in white adipose cells (WAT) is usually decreased in obese mice. 10Adipose-specific FGFR1 knockout mice exhibit a normal body weight and physiological functions, but not the FGF21 treatment-induced decrease in body weight, plasma glucose, insulin and triglyceride observed in wild-type mice. 12, 13On the other hand, HQL-79 adipose-specific FGFR2 knockout mice display hypertrophic adipocytes in the mesenteric WAT but not in the subcutaneous WAT. 14The role of FGFR2c in the development of obesity and type 2 diabetes, however , remains unclear. Aymice with ectopic overexpression of agouti peptide, an endogenous melanocortin-4 receptor antagonist, are known to become obese and insulin-independent diabetes, when bred with KK mice. 15Social isolation promotes weight problems due to the HQL-79 main decreased energy expenditure and the insulin-independent diabetes associated with increased expression of hepatic gluconeogenic genes in KKAymice. 15 To determine the role of FGFR2c in the development of obesity and type 2 diabetes induced by social isolation, we examined the effect of mouse FGFR2-IIIc monoclonal antibody on food intake, body weight changes, epididymal WAT (eWAT), blood glucose, and plasma-free fatty acids and FGF21 levels, and the expression of uncoupling protein-1 (UCP-1), UCP-2 and peroxisome proliferator-activated receptor- coactivator 1 (PGC1) in the eWAT of individually housed KKAymice. == Materials and Methods == Four-week-old male KKAyand KK mice were purchased coming from Japan CLEA. Before the experiment, they were almost all housed (three mice per cage) with free access to water and chow pellets in a light- and temperature-controlled environment (12 h on/12 h off, lights on at 08: 00; 2022 C). One week later, animals were transferred to individually housed conditions because described previously. 15 Five-week-old male KKAyand KK mice were intraperitoneally injected mouse monoclonal FGFR2- IIIc antibody (0. 05 mg kg1) or saline once per day over 6 days. The animals were provided chow pellets after the injection. Every 24 h later, body weight and food intake were assessed. At the end from the 6 HQL-79 days, the animals were decapitated and blood was obtained for the measurement of blood glucose and plasma FFA and FGF21 levels. The eWAT was removed to get the measurement of mRNA. Mouse FGFR2-IIIc antibody was purchased coming from R&D Systems, Tokyo, Japan. The drugs were dissolved in 0. 2 ml 0. 9% saline. The dose of mouse FGFR2-IIIc used was described previously. 16The experiment was performed between 13: 0016: 00. Whole blood was mixed with EDTA-2Na (2 mg ml1) and aprotinin (500 kIU ml1) to determine the plasma levels of FGF21. Blood glucose levels were measured using glucose strips (Blood glucose monitoring system; FreeStyle, KISSEI, Tokyo, Japan). The plasma FFA levels were assessed by ACS-ACOD- POD assay (NEFA-SS EIKEN (Eiken Chemical co, Ltd, Tokyo, Japan). The plasma levels of FGF21 were assessed by an enzyme-linked immunosorbent assay (ELISA) (rat/mouse FGF21 ELISA packages; R&D system). The animal studies were conducted in accordance with the institutional guidelines for creature experiments at the Tohoku University Graduate School of Medicine. == Real-Time Quantitative RT-PCR == Total RNA was isolated from Rabbit Polyclonal to VIPR1 mouse eWAT using the RNeasy In addition Universal Midi kit (Qiagen, Hilden, Germany) according to the manufacturer’s directions. cDNA synthesis was performed using a Super Script III First-Strand Synthesis System for RT-PCR Kit (Invitrogen, Rockville, MD) using 1 g total RNA. cDNA synthesized coming from total RNA was evaluated in a real-time PCR quantitative system (LightCycler Nano Instrument.