title: Impact of fasting time on hepatic lipid metabolism in nutritional animal studies.
abstract: Many animal studies on improvement of lipid metabolism, using dietary components, fast the animals on the final day of the feeding. Although fasting has a significant impact on lipid metabolism, its time-dependent influence is not fully understood. We examined the effects of several fasting times on lipid metabolism. Rats fed with a semisynthetic diet for 2 wk were killed after 0 (9:00 am), 6 (7:00 am-1:00 pm), 9 (0:00 am-9:00 am), and 13 h (8:00 pm-9:00 am) of fasting. Compared to the 0 h group, marked reduction of liver weight and hepatic triacylglycerol content was observed in the 9 and 13 h groups. Activities of hepatic enzymes involved in fatty acid synthesis gradually decreased during fasting. In contrast, drastic time-dependent reduction of gene expression, of the enzymes, was observed. Expression of carnitine palmitoyltransferase mRNA was higher in the fasting groups than in the 0 h group. Our study showed that fasting has a significant impact on several parameters related to lipid metabolism in rat liver.
authors.affiliation: a Laboratory of Food and Biomolecular Science, Graduate School of Agricultural Science , Tohoku University , Sendai , Japan.
authors.forename: Ikuo
authors.initials: I
authors.lastname: Ikeda
authors.forename: Kanae
authors.initials: K
authors.lastname: Metoki
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamahira
authors.forename: Masaki
authors.initials: M
authors.lastname: Kato
authors.forename: Nao
authors.initials: N
authors.lastname: Inoue
authors.forename: Koji
authors.initials: K
authors.lastname: Nagao
authors.forename: Teruyoshi
authors.initials: T
authors.lastname: Yanagita
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Shirakawa
authors.forename: Michio
authors.initials: M
authors.lastname: Komai
mesh_terms: D000818:Animals; D002334:Carnitine O-Palmitoyltransferase / Q000096:biosynthesis*; D005215:Fasting / Q000378:metabolism / Q000502:physiology*; D015971:Gene Expression Regulation, Enzymologic; D050356:Lipid Metabolism / Q000235:genetics*; D008099:Liver / Q000201:enzymology / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats
chemical_list: D012333:RNA, Messenger; D002334:Carnitine O-Palmitoyltransferase
keywords: abdominal fat; fatty acid synthesis; liver; triacylglycerol; β-oxidation