Beckman glucose analyser 2

Serum glucose concentrations were measured in duplicate by the glucose oxidase method using a Beckman glucose analyser II (Beckman Instruments, Brea, California). Glycosylated haemoglobin (HbA1c) was measured by the high-performance liquid chromatography method (Bio-Rad, Muenchen, Germany, and autoanalyser Jokoh HS-10, respectively). Intra-and inter-assay coefficients of variation were less than 4% for all these tests. Serum insulin was measured in duplicate by RIA (Medgenix Diagnostics, Fleunes, Belgium). The intra-assay coefficient of variation was 5.2% at a concentration of 10 mU/l and 3.4% at 130 mU/l. The interassay coefficients of variation were 6.9% and 4.5% at 14 and 89 mU/l, respectively. HOMA-IR was calculated using the following formula: [Insulin (mU/l) x Glucose mmol/l]/22.5. Roche Hitachi Cobas c711 instrument (Roche, Barcelona, Spain) was used to do HDL cholesterol and total serum triglycerides determinations. HDL cholesterol was quantified by a homogeneous enzymatic colorimetric assay through the cholesterol esterase / cholesterol oxidase / peroxidase reaction (Cobas HDLC3). Serum fasting triglycerides were measured by an enzymatic, colorimetric method with glycerol phosphate oxidase and peroxidase (Cobas TRIGL). LDL cholesterol was calculated using the Friedewald formula.

From the cut tip of the tail vein of conscious mice, blood samples were collected into fluoride/ heparin microcentrifuge tubes (Sarstedt, Numbrecht, Germany) at the times indicated in the Figures. Samples were immediately centrifuged (Beckman microcentrifuge; Beckman Instruments, High Wycombe, UK) for 30 s at 13,000 g and resulting plasma was stored at -20°C until analysis. Plasma and pancreatic insulin levels were determined by an insulin radioimmunoassay as described previously [18] . Plasma glucose was assayed by an automated glucose oxidase procedure using a Beckman Glucose Analyser II (Beckman Instruments, Galway, Ireland).

Serum glucose concentrations were measured in duplicate by the glucose oxidase method using a Beckman glucose analyser II (Beckman Instruments, Brea, CA, USA). A Roche Hitachi Cobas c711 instrument (Roche, Barcelona, Spain) was used to determine HDL-cholesterol and total serum triacylglycerols. HDL-cholesterol was quantified by a homogeneous enzymatic colorimetric assay through the cholesterol esterase-cholesterol oxidase-peroxidase reaction (Cobas HDLC3). Serum fasting triacylglycerols were measured by an enzymatic, colorimetric method with glycerol phosphate oxidase and peroxidase (Cobas TRIGL).