Additionally, plasma samples were collected from 4-h fasted animals at week 15 (collected 1 week prior to week 16 blood samples, to avoid the fasting interfering with plasma lipid parameters) and assayed for endogenous insulin and glucose. Samples for blood glucose measurements (10 µL) were collected in capillary tubes and transferred to 500 µL system solution. Blood glucose levels were analyzed using the glucose oxidase method at a Biosen apparatus (EKF Diagnostics, Barleben, Germany) according to manufacturer’s instructions. Samples for endogenous insulin measurements were collected in K3-EDTA microvettes and after centrifugation; plasma was isolated and analyzed as previously described . Leptin levels were quantified using a Milliplex assay (RADPKMAG80-K, Merck, Hellerup, DK).