Serine utilization in mouse liver: influence of caloric restriction and aging.
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.
Hagopian
Kevork
K
Department of Molecular Biosciences, School of Veterinary Medicine, University of California, One Shields Ave, Davis, CA 95616, USA. khagopian@ucdavis.edu
Ramsey
Jon J
JJ
Weindruch
Richard
R
D000375:Aging / Q000378:metabolism*; D000818:Animals; D031204:Caloric Restriction; D005943:Gluconeogenesis / Q000502:physiology; D012695:L-Serine Dehydratase / Q000502:physiology*; D008099:Liver / Q000201:enzymology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000502:physiology; D012694:Serine / Q000378:metabolism*; D000637:Transaminases / Q000502:physiology
D012694:Serine; D000637:Transaminases; C022638:serine-pyruvate aminotransferase; D017853:Phosphotransferases (Alcohol Group Acceptor); C020670:glycerate kinase; D012695:L-Serine Dehydratase