Effects of -Hydroxybutyrate (HB) on L6 Muscle cell Glucose and Fat Metabolism

This study investigated the effects of the ketone body -hydroxybutyrate (HB) on glucose and fat metabolism in skeletal muscle cells. To accomplish this, L6 muscle cells were incubated with various HB concentrations (0.5, 1.0, 1.5, 20, and 2.5 mM) for 1, 3, and 5 days. Here, we report that HB significantly increased glucose uptake and its metabolism in L6 muscle cells. Time course analysis revealed that as early as 1 day of exposure to 1mM HB significantly enhanced basal and insulin-stimulated glucose uptake (1.6-fold), glycogen synthesis (1.3-fold), glucose oxidation (1.5-fold), and lactate production (1.3-fold) in skeletal muscle cells. Even though carnitine palmitoyl transferase 1 (CPT1) content and AMP-activated protein kinase (AMPK) phosphorylation significantly increased, no alteration was found in palmitate oxidation with HB treatment. Surprisingly, protein kinase B (AKT) phosphorylation was significantly reduced in muscle cells exposed to HB. In summary, HB increased AMPK phosphorylation and enhanced glucose uptake without altering fatty acid oxidation in skeletal muscle cells.