title: Down Regulation of Asparagine Synthetase and 3-Phosphoglycerate Dehydrogenase, and the Up-Regulation of Serine Dehydratase in Rat Liver from Intake of Excess Amount of Leucine Are Not Related to Leucine-Caused Amino Acid Imbalance.
abstract: Asparagine synthetase (ASNS), 3-phosphoglycerate dehydrogenase (PHGDH) and serine dehydratase (SDS) in rat liver are expressed in response to protein and amino acid intake. In the present study, we examined the expression of these enzymes in relation to amino acid imbalance caused by leucine. Rats were subjected to leucine administration in the diet or orally between meals. Consumption of more than 2% leucine in a 6% casein diet suppressed food intake and caused growth retardation in a dose-dependent manner, but this was not seen in a 12% or 40% casein diet. ASNS and PHGDH expression in the liver was significantly induced by the 6% casein diet and was suppressed by leucine in a dose-dependent manner, whereas the SDS expression was induced. These effects were leucine specific and not seen with ingestion of isoleucine or valine. However, leucine orally administered between meals did not change the food intake or growth of rats fed a 6% casein die, though it similarly affected the expression of ASNS, PHGDH and SDS in the liver. These results suggest that the growth retardation caused by leucine imbalance was mainly because of the suppression of food intake, and demonstrated that there are no causal relationships between ASNS, PHGDH and SDS expression and amino acid imbalance caused by leucine.
authors.affiliation: Laboratory of Molecular Nutrition, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University.
authors.forename: Ryoji
authors.initials: R
authors.lastname: Yoshimura
authors.forename: Marie
authors.initials: M
authors.lastname: Takai
authors.forename: Hiroya
authors.initials: H
authors.lastname: Namaki
authors.forename: Kimiko
authors.initials: K
authors.lastname: Minami
authors.forename: Wataru
authors.initials: W
authors.lastname: Imamura
authors.forename: Hisanori
authors.initials: H
authors.lastname: Kato
authors.forename: Yasutomi
authors.initials: Y
authors.lastname: Kamei
authors.forename: Ryuhei
authors.initials: R
authors.lastname: Kanamoto
mesh_terms: D000596:Amino Acids / Q000008:administration & dosage / Q000378:metabolism; D000818:Animals; D001217:Aspartate-Ammonia Ligase / Q000378:metabolism*; D001835:Body Weight; D002364:Caseins / Q000008:administration & dosage; D004032:Diet; D015536:Down-Regulation; D004435:Eating / Q000187:drug effects*; D002149:Energy Intake / Q000187:drug effects; D006128:Growth / Q000187:drug effects; D006706:Homeostasis / Q000187:drug effects; D007532:Isoleucine / Q000494:pharmacology; D012695:L-Serine Dehydratase / Q000378:metabolism*; D007930:Leucine / Q000008:administration & dosage / Q000009:adverse effects*; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D050543:Phosphoglycerate Dehydrogenase / Q000378:metabolism*; D017207:Rats, Sprague-Dawley; D015533:Transcriptional Activation; D015854:Up-Regulation; D014633:Valine / Q000494:pharmacology
chemical_list: D000596:Amino Acids; D002364:Caseins; D007532:Isoleucine; D050543:Phosphoglycerate Dehydrogenase; D012695:L-Serine Dehydratase; D001217:Aspartate-Ammonia Ligase; D007930:Leucine; D014633:Valine