GLUCONEOGENESIS FROM SERINE IN RAINBOW-TROUT SALMO-GAIRDNERI LIVER

1. 1. The pathway(s) of gluconeogenesis from serine, in rainbow trout liver were studied. 2. 2. Enzyme distribution studies revealed a lack of serine dehydratase activity, but relatively high levels of serine pyruvate transaminase (SPT). Glycerate dehydrogenase and glycerate kinase, required in addition to SPT, for the conversion of serine to 2-phosphoglycerate, were also present. These enzymes had a predominantly mitochondrial location. 3. 3. In studies with isolated hepatocytes, glucose production from serine proceeded at a rate of 5.7 μmol/hr per g. Gluconeogenesis was stimulated by the presence of 1 mM pyruvate or alanine, but strongly inhibited by 0.2 mM aminoxyacetate. 4. 4. The results show that in contrast to adult rat liver, gluconeogenesis from serine in trout liver proceeds via the SPT initiated pathway. © 1979.