Effect of Thiamin Derivative on Carbohydrate Metabolism at Rest in Mice

Abstract

Thiamin is known to activate carbohydrate metabolism by the activation of pyruvate dehydrogenase (PDH). We previously reported that thiamin tetrahydrofurfuryl disulfide (TTFD), which is a derivative of thiamin, inhibits oxidation of exogenous glucose at rest, but not during exercise. Furthermore, concentrations of muscle and liver glycogen tended to be lower after TTFD ingestion during recovery from endurance exercise. Therefore, it could be hypothesized that administration of a thiamin derivative inhibited glycogen synthesis from glucose in muscle and liver and changed liver cytosolic glucose-induced lipogenesis via pentosephosphate pathway, which involves the other thiamin sensitive transketolase (TK) reaction. PURPOSE: To investigate the effect of TTFD on carbohydrate metabolism in liver and skeletal muscles at rest. METHODS: Seven-week-old male ICR mice were randomly assigned to a TTFD ingestion group or a water ingestion group. Mice orally ingested glucose (0.8 mg/g BW) plus water or TTFD (0.1 mg/g BW). Concentrations of blood substrates, muscle and liver glycogen and liver TK activity were measured at rest. RESULTS: No significant effect of TTFD was found in concentrations of blood lactate and glucose at rest. Blood free fatty acid concentrations were significantly lower in TTFD group than in water group (P<0.01). Concentration of muscle glycogen was significantly lower in TTFD mice than in control mice (P<0.05), but no significant difference was found in liver glycogen. Liver TK activity was lower in TTFD group (P<0.05). Therefore, single treatment of TTFD and glucose might suppress liver glucose-induced lipogenesis via pentose phosphate pathway. CONCLUSIONS: These results indicate that TTFD, a derivative of thiamin, which has been known to activate glucose metabolism, decreased glycogen concentration in skeletal muscle and blood free fatty acid concentration at rest.