Chemical assay kit

Before being placed on the experimental diets, rat body weights were recorded and then taken weekly. Fasting blood glucose measurements were taken weekly using a One Touch Glucometer (Johnson and Johnson). At the initiation of the diet, each rat was placed in a metabolic cage with access to water solely for a 24-hour urine collection. Glomerular filtration rate (GFR) based on creatinine clearance was determined using urine and plasma creatinine assay kits (Cayman Chemicals, Ann Arbor, MI, number 500701 and number 700460) and urine output levels. GFR was calculated by urine concentration multiplied by the urine output, all divided by plasma concentration. cGMP urine levels were measured using a kit from Cayman Chemicals (Cayman Chemicals, Ann Arbor, MI, number 581021). Plasma nitrotyrosine measurements were made using a nitrotyrosine assay kit (Hycult Laboratories, Uden, the Netherlands, number HK501). These measurements were repeated at experimental times of 3, 6, and 8 weeks. A glucose tolerance test (GTT) was performed at week 6. Blood glucose readings for the GTT were taken at 0, 15, 30, 60, 90, 120, and 150 minutes after intraperitoneal injection of glucose. Plasma nitrite levels were measured using a chemical assay kit (Cayman Chemicals, number 780001) and were tested at weeks 0 and 8.

HFFs were treated with different concentrations (0.25,0.5, 1, and 2 μg/ml) in a 6-well plate for 24 h, and then total intracellular glutathione (GSH) content was determined using a chemical assay kit (Cayman Chemical, Ann Arbor, MI, USA) following the manufacturer’s instructions.