In vivo incorporation of lipoic acid enantiomers and homologues in the pyruvate dehydrogenase complex from Escherichia coli

Inhibition of glucose production and stimulation of bile flow by R (+)‐α‐lipoic acid enantiomer in rat liver

“…In isolated hepatocytes obtained from long‐term fasted rats (18), 10 −3 −10 −4 mol L −1 racemic α‐lipoic acid inhibited gluconeogenesis from the precursors lactate, pyruvate and alanine. Recent studies provided evidence that short‐term effects of RLA are not only because of the reaction with dihydrolipoyl acetyltransferase, leading to higher activity of PDH (3, 19), but also could be the result of an insulin‐like effect as observed in adipocytes (20). At high concentrations of 1–5 mmol L −1 , RLA dose‐dependently stimulated uptake of 2‐deoxyglucose and phosphorylation of IRS‐1 and PI3 kinase (20).…”

“…In isolated hepatocytes obtained from long-term fasted rats (18), 10 À3 À10 À4 mol L À1 racemic a-lipoic acid inhibited gluconeogenesis from the precursors lactate, pyruvate and alanine. Recent studies provided evidence that short-term effects of RLA are not only because of the reaction with dihydrolipoyl acetyltransferase, leading to higher activity of PDH (3,19), but also could be the result of an and 10 À3 mol L À1 RLA (n 4, µ). Insert: rates of glucose production (in mmolÁmin À1 Ág À1 liver, calculated from the slope of a linear curve ®tting procedure applied to the concentration time curve from 0 to 90 min).…”