title: Sequential responses to high-fat and high-calorie feeding in an obese mouse model.
abstract: OBJECTIVE
  Reports on the immediate and long-term responses to high-fat and high-calorie (HFC) feeding are controversial. Therefore, we examined the sequential effects of an HFC diet.
  
  
  METHODS
  C57BL/6J mice were randomly assigned to consume either the control (C) or the HFC diet. Body weights and food intake were measured weekly and other measurements at weeks 2, 4, and 10. Microarrays were used for screening the transcriptional response of the livers at the three time points. Genes, encoding enzymes regulating key steps of lipid metabolism, were then selected from the microarray data for validation by quantitative real-time reverse-transcription polymerase chain reaction (qRT-PCR) and their protein expression by western blot assays.
  
  
  RESULTS
  Mice fed with HFC diet for 2 weeks showed no increase in food intake and no difference in weight gain compared to the C mice. At weeks 4 and 10, the HFC mice increased their food intake and gained more weight than their controls (by 1.4 times and 2.5 times, respectively) (P<0.01 at week 10). Genes involved in fatty acid oxidation (FAO) were initially upregulated and then downregulated, whereas the lipogenic genes and genes involved in cholesterol synthesis showed reverse trends. The differential mRNA expression of Cpt1L, Fas, and Hmgcr were confirmed by RT-PCR and their protein expression by western blot assays.
  
  
  CONCLUSIONS
  Our findings suggested that when mice were fed an HFC diet, they could develop initial compensatory response to resist the increased energy balance; however, a prolonged consumption of an HFC diet appeared to disrupt this adaptation.
authors.affiliation: Department of Pediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Mei-Yen
authors.initials: MY
authors.lastname: Chan
authors.forename: Yulan
authors.initials: Y
authors.lastname: Zhao
authors.forename: Chew-Kiat
authors.initials: CK
authors.lastname: Heng
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight / Q000187:drug effects / Q000502:physiology; D004041:Dietary Fats / Q000494:pharmacology*; D004195:Disease Models, Animal; D004435:Eating / Q000187:drug effects / Q000502:physiology; D002149:Energy Intake / Q000502:physiology*; D004734:Energy Metabolism / Q000187:drug effects* / Q000502:physiology; D005260:Female; D020869:Gene Expression Profiling; D006706:Homeostasis; D050356:Lipid Metabolism / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D008055:Lipids / Q000097:blood; D051379:Mice; D008810:Mice, Inbred C57BL; D009765:Obesity / Q000378:metabolism / Q000503:physiopathology*; D012333:RNA, Messenger / Q000378:metabolism; D011897:Random Allocation
chemical_list: D001786:Blood Glucose; D004041:Dietary Fats; D008055:Lipids; D012333:RNA, Messenger