AbstractThe pathway of β‐alanine (BALA) oxidation was examined in the liver of the little skate,Raja erinacea.BALA oxidation in liver slices was reduced by inhibitors of transamination and mitochondrial electron transport. Experiments with liver homogenates indicated that BALA was oxidized by a two step process: (1) transamination of BALA to malonate semialdehyde (MSA) and (2) conversion of MSA to CO2and acetate. Increases in BALA oxidation during osmotic stress are probably mediated by changes in substrate concentration rather than alterations in enzyme leve