Tolbutamide (HLS 831) is a sulphonylurea hypoglycemic agent with actions and uses similar to those of CHLORPROPAMIDE.

cAMP stimulated protein kinase:4 mM

cAMP kinase assay: Diced epididymal fat pads from fed Wistar rats (175-225 gm) are obtained after decapitation and incubated at 37 °C for two hours in Krebs-bicarbonate buffer containing 1.27 mM CaCl2. When added, Tolbutamide is present only during the incubation. After incubation fat pads are rinsed and sonicated in cold Krebs-bicarbonate buffer. The aqueous supematants from centrifugation at 50,000 × g for 30 minutes at 4 °C contained 0.75 to 1.25 mg protein per mL and are assayed for cyclic AMP-stimulated protein kinase activity. The assay is performed in 0.2 mL with these additions, 10 μmoles sodium glycerofiosphate pH 7.0, 2 μmoles sodium fluoride, 0.4 μmoles theophylline, 0.1 μmoles ethylene glyool bis (β-aminoethyl ether)-N, N'-tetraaoetic acid, 3 μmoles magnesium chloride, 0.3 mg mixed histone, 2 nmoles (γ- 32P) ATP, 1 nmoles cyclic AMP when indicated, and 0.05 ml of supernatant.

C6 glioma cells are incubated in serum-free DMEM at 37 °C for at least 24 hours before each experiment. Tolbutamide (400 μM) is incubated for 24 hours in serum-free medium. Incubations are performed at 37 °C in an atmosphere of 95% air/5% CO2 with 90–95% humidity. (Only for Reference)