pants were not taking any medication known to affect glucose tolerance or insulin secretion. From the overall cohort, a subgroup of 486 subjects voluntarily agreed to undergo a hyperinsulinaemic-euglycaemic clamp and a subgroup thereof additionally magnetic resonance imaging and spectroscopy. The clinical characteristics of the overall cohort and the clamp and MRI/MRS subgroups are given in OGTT A standardized 75-g OGTT was performed after a 10-h overnight fast, and 946128-88-7 biological activity venous blood samples were drawn at timepoints 0, 30, 60, 90, and 120 min for the determination of plasma glucose and insulin concentrations. Hyperinsulinaemic-euglycaemic clamp After a 10-h overnight fast and a 60-min baseline period, subjects received a priming dose of insulin followed by an infusion of short-acting human insulin for 120 min. A variable infusion of 20% glucose was started to maintain the plasma glucose concentration at 5.5 mmol/L. Blood samples for the measurement of plasma glucose were obtained at 5-min intervals throughout the clamp, plasma insulin levels were measured at baseline and in the steady state of the clamp. Measurements of body fat content and distribution Body mass index was calculated as weight divided by height squared. Waist circumference was measured in the upright position at the midpoint between the lateral iliac crest and the lowest rib. The percentage of body fat was measured by bioelectrical impedance. In addition, total and visceral fat contents were determined by MRI with an axial T1weighted fast-spin echo technique with a 1.5-T ” whole-body imager, as described earlier. The intrahepatic lipid content was determined by localized STEAM 1 H-MRS in the 7th segment of the liver, as formerly reported. Laboratory measurements Plasma glucose was determined using a bedside glucose analyzer. Plasma insulin concentrations were measured by a commercial chemiluminescence assay for ADVIA Centaur according to the manufacturer’s instructions. Fasting plasma leptin “7851504 and PEDF concentrations were determined by enzyme-linked immunosorbent assays. Materials and Methods Ethics statement Informed written consent to the study was obtained from all participants. The study adhered to the Declaration of Helsinki, and the study protocol was approved by the Ethics Committee of the Medical Faculty of the Eberhard Karls University Tubingen. Subjects A study cohort of 1,974 White European individuals was recruited from the ongoing Tubingen family study for type 2 diabetes that currently encompasses more than 2,000 participants at increased risk for type 2 diabetes . All participants underwent the standard procedures of the study protocol including assessment of medical history, smoking status and alcohol consumption habits, physical examination, routine blood tests, and an oral glucose tolerance test. Selection of the present study cohort was based on the absence of newly diagnosed diabetes and the availability of complete sets of phenotype and 
Selection of tagging single nucleotide polymorphisms Based on the publicly available phase III data of the International HapMap Project derived from the CEU population of Utah residents with ancestry from Northern and Western Europe, we screened in silico the complete SERPINF1 gene spanning 15.6 kb as well as 4 and 1.5 kb of its 59- and 39flanking regions, respectively. The genotyping success rates were $99.7%. The Sequenom results were validated by bidirectional sequencing in 50 randomly selected subjects, and both methods g