1 13c glucose

R-sodium lipoic acid was a gift from GeroNova Research. A constant infusion of [1-¹³C]-glucose and [1,2-¹³C]-acetate was performed by using the ECONO gradient pump (Bio-Rad Laboratories, Hercules, CA, USA) and Rodent tail vein catheter and restraining apparatus (Braintree Scientific). Deuterium oxide (99.9%) and [1,2-¹³C]-acetate (99%) (Cambridge Isotope Laboratories, Andover, MA, USA), [1-¹³C]-glucose (99%) (Sigma-Aldrich, St Louis, MO, USA) were used for the NMR experiments. Chemicals of the purest grade were used for all assays. The primary antibodies against β-actin (SC-1616), GLUT3 (SC-74399), GLUT4 (sc-1608), Na⁺/K⁺-ATPase (SC-58628), and HRP-labeled secondary antibodies were obtained from Santa Cruz Biotechnology (Dallas, Texas, USA). Antibodies for Akt (9272) and p-Akt (Ser⁴⁷³) (9271) were purchased from Cell Signaling Technology (Danvers, MA, USA).

[1-¹³C]glucose (99%) was purchased from Sigma-Aldrich (St Louis, MO, USA); [1,2-¹³C]acetate (99%) and D₂O (99.9%) from Cambridge Isotope Laboratories (Andover, MA, USA); the rodent tail vein catheter and restraining apparatus from Braintree Scientific, Inc. (MO, USA); the constant infusion of [1-¹³C]glucose and [1,2-¹³C]acetate was carried out by using a pump from Bio-Rad Laboratories Inc. (CA, USA). All other chemicals were the purest grade available from Sigma-Aldrich.