Serine utilization in mouse liver: Influence of caloric restriction and aging

Abstract

The influence of caloric restriction (CR) on the activities of hepatic serine metabolizing enzymes in young (3 months) and old (30 months) mice was studied. Serine dehydratase (SDH) activity increased markedly with age in both diet groups and in old mice was higher in the CR group. No effects of CR were observed in the young. Serine:pyruvate transaminase (SPT) and glycerate kinase activities were unaffected by age and diet. However, glycerate dehydrogenase activity was decreased in old CR mice but not in young CR. The results of this study show that long-term CR influenced serine utilization only in the pathway catalyzed by SDH. This suggests that in mouse liver this pathway is critical for serine utilization in gluconeogenesis, while the SPT pathway plays a minor role. The increase in SDH activity with long-term CR is consistent with sustained increase in gluconeogenesis.

Prednisolone-induced differential gene expression in mouse liver carrying wild type or a dimerization-defective glucocorticoid receptor

“…Among the upregulated genes are Pck1 , encoding the rate limiting enzyme in gluconeogenesis [35], Ppargc1a ( Peroxisome proliferative activated receptor, gamma, coactivator 1 alpha ), a transcriptional coactivator that coordinates the expression of genes involved in gluconeogensis and ketogenesis [36], and Sds ( Serine dehydratase ) and Aass ( Aminoadipate-semialdehyde synthase ), two genes encoding enzymes involved in amino acid catabolism and amino acid utilization for gluconeogenesis [37,38]. …”

Characterization of glycerate kinase (2-phosphoglycerate forming), a key enzyme of the nonphosphorylative Entner–Doudoroff pathway, from the thermoacidophilic euryarchaeonPicrophilus torridus

“…Hyphomicrobium, Methylobacterium (Yoshida et al, 1992;Chistoserdova , 1997), where the enzyme is involved in formaldehyde assimilation via the serin pathway. In Escherichia coli a 2-phosphoglycerate forming glycerate kinase has been implicated in glucarate and galacturate degradation (Hubbard et al, 1998), in Flavobacterium in ethylene glycol degradation (Willetts, 1978) and in mammals in serine metabolism (Hagopian et al, 2005). A 2-phosphoglycerate forming glycerate kinase activity has also been reported for the hyperthermophilic euryarchaeon Pyrococcus furiosus (Schäfer & Schönheit, 1992).…”

Enzymes of glycerol and glyceraldehyde metabolism in mouse liver: effects of caloric restriction and age on activities

“…The adaptations in energy metabolism under sustained CR conditions have not been well defined, and it is not known if changes in energy metabolism occur after dynamic weight loss has ceased. In previous studies [17,[23][24][25][26], we have reported the influence of CR on other major metabolic pathways. The aim of this study was to characterize and establish the effects of long-term CR and aging on the glycerol and glyceraldehyde metabolizing enzymes.…”