The metabolic fate and metabolic effects of succinic acid methyl esters were examined in rat isolated hepatocytes. Both the monomethyl ester (SAM) and dimethyl ester (SAD) of succinic acid inhibited D-glucose metabolism. Such an inhibition affected, in order of increasing severity, the direct incorporation of D-glucose into glycogen and futile cycling between the hexose and its 6-phosphate ester, the phosphorylation of D-glucose, the generation of triose phosphates from the hexose, and the production of 14C-labeled lactate, pyruvate, and amino acids from D-[U-14C]glucose and its oxidation. The dimethyl ester of [1,4-14C]succinic acid ([1,4-14C]SAD) or [2,3-14C]-succinic acid ([2,3-14C]SAD) was efficiently converted to acidic metabolites. The oxidation of [1,4-14C]SAD largely exceeded that of [2,3-14C]SAD. Inversely the generation of newly formed radioactive D-glucose and glycogen appeared higher in cells exposed to [2,3-14C]SAD, rather than [1,4-14C]SAD. It is proposed that SAM and SAD are suitable nutrients both to cover the energy need of hepatocytes and to act as gluconeogenic precursors.