The obesogenic effects of polyunsaturated fatty acids are dependent ...

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described in Table 1 and 2. The fish oil enriched diets contained 62 ± 3 g/kg n-3 fatty acids, thereof
27 ± 3 g/kg and 18 ± 3 g/kg EPA and DHA, respectively. All diets were supplemented with 3g/kg
L-cysteine, 10g/kg choline bitartrate, 10g/kg vitamin mix AIN 76 A, 45 g/kg mineral mix AIN 93
and 0.014 g/kg t-butylhydroquinone. As indicated Nifedipine (N7634, Sigma) was included in the
diet at a dose (1g/kg) earlier demonstrated to reduce plasma insulin levels in agouti mice (34). The
sulfonylurea Glybenclamide (G0639, Sigma) was used as an insulin secretagogue and was
administrated daily by intraperitoneal (i.p.) injection at a dose of 2 μg/g body weight..Control mice
received placebo. by daily i.p. injection. Mice in the fed state were euthanized by cardiac puncture
under anesthesia with isoflurane (Isoba-vet, Schering-Plough, Denmark) using the Univentor 400
Anaesthesia Unit (Univentor Limited, Sweden) and plasma was prepared from blood. Tissues were
dissected out, freeze-clamped and frozen at -80 o C. All animal experiments were approved by
National Animal Health Authorities (Denmark and Norway). Adverse events were not observed.
Energy measurements and digestibility. Male C57BL/6JBomTac mice (n=5 for each group) were
fed experimental diets ad libitum for 4 days. Faeces, urine and feed residue were collected during a
24h period before respiration measurements. The nitrogen content in feed, faeces, and urine was
determined using the Tecator-Kjeltec system 1026 (Tecator AB, Höganäs, Sweden). The gross
energy content of feed and faeces was determined using an adiabatic bomb calorimeter (System
C700, IKA Analysentechnic GmbH, Heitersheim, Germany).
Glucose and insulin tolerance testing (GTT and ITT). GTT: mice were fasted 6 hours before i.p
injection of 2 g/kg glucose in saline. ITT: mice were fasted 4 hours before i.p. injection of 0.5
Unit/kg human recombinant insulin in saline. Blood was collected from the lateral tail vein at
indicated time points and blood glucose was measured with a Bayer Contour glucometer (Bayer
A/S, Denmark).
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