hCRP was administered by a single intravenous injection of 2.5 mg/kg and blood samples were collected for measurement of hCRP at regular time intervals for up to 3 hours. This dose was selected after conducting NVP-AUY922 cost pilot studies to achieve serum hCRP concentrations comparable to the extensively used hCRP transgenic mouse model.21 Indwelling catheters were inserted into the right jugular vein and the left carotid artery of rats under general anesthesia (ketamine 75 mg/kg, xylazine 10 mg/kg, intraperitoneally) and exteriorized from the back of the neck. Meloxicam was administered as the postoperative analgesic once daily for 2 days consecutively. Rats

were allowed to fully recover and only those that had lost less than 5% of their preoperative weights were used. Euglycemic-hyperinsulinemic clamps were performed on fasted, awake, and unrestrained animals. The experiments consisted of a basal period (−90 to 0

minutes) and a clamp period (0 to 120 minutes). High-performance liquid chromatography (HPLC)-purified [3-3H]glucose (Perkin-Elmer, Boston, MA) was administered as a bolus of 8 μCi followed by infusion at 0.2 μCi/min from −90 to 0 minutes and at 0.4 μCi/min from 0 to 120 minutes to assess endogenous glucose production (EGP) and whole-body glucose disposal (Rd). hCRP (2.5 mg/kg) or hCRP solvent (vehicle) was administered through the jugular selleck chemical vein at −40 minutes. We have demonstrated in separate clamp experiments that the effect of hCRP solvent on insulin sensitivity does not differ from that of human serum albumin (see online data supplement for details), hence the simpler hCRP solvent was used throughout as a control for in vivo, ex vivo, and in vitro experiments.

A bolus of insulin (45 mU/kg, MCE公司 Eli Lilly, Indianapolis, IN) was administered at 0 minutes followed by infusion at 2 mU/kg/min for the remainder of the clamp study. A variable infusion of 25% dextrose was adjusted every 10 minutes to clamp the blood glucose at basal levels. Arterial samples were drawn at −90 (baseline), −30, −20, −10, 0, 60, 80, 90, 100, 110, and 120 minutes for further analyses. The rate of appearance of glucose determined with [3-3H]glucose was calculated using Steele’s equation. Animals underwent the same surgery as described above for the clamp study. After an overnight fast, hCRP (2.5 mg/kg) was administered by way of the jugular vein. Then, 150 minutes later, under anesthesia by sodium pentobarbital (45 mg/kg, intraperitoneally) blood samples were collected for determination of TNF-α, IL-6, leptin, and adiponectin. Liver tissues were excised, snap-frozen in liquid nitrogen, and stored at −80°C. For insulin signaling measurements, including IRS/PI3K association, tyrosine phosphorylation (pY), and Akt phosphorylation, liver tissues were removed at 2 minutes after an intravenous bolus of saline or insulin (10 U/kg). For measurements of MAPKs and IRS-1 serine phosphorylation, no insulin was administered before removing liver tissues.