title: Predicting the effects of a high-energy diet on fatty liver and hippocampal-dependent memory in male rats.
abstract: OBJECTIVE
  In rodents, diets exceeding nutritional requirements (i.e., high-energy diets; HED) impair hippocampal-dependent memory. Our research suggests that the effects likely involve HED-induced increases in liver lipids. In this experiment, rats were provided with diet choices to test whether voluntary consumption of a HED impairs spatial memory, whether differences in initial weight gain predict memory deficits, and whether increases in liver lipids are associated with the memory deficits.
  
  
  METHODS
  Adult male Sprague-Dawley rats were given a control diet or cafeteria-style HED for 8 weeks. Weight gain during the first 5 days on the diet was used to divide rats into a HED-Lean group and a HED-Obese group. Spatial water maze memory was tested 8 weeks later and postmortem liver lipid concentrations were quantified.
  
  
  RESULTS
  Compared with the HED-Lean and control rats, the HED-Obese rats had impaired spatial memory and met the human diagnostic criterion of non-alcoholic fatty liver disease (>5% liver lipids relative to liver weight). Moreover, liver lipids were correlated with memory deficits.
  
  
  CONCLUSIONS
  These findings show that voluntary consumption of a HED impairs memory, that initial weight gain predicts fatty liver and memory deficits, and that fatty liver may contribute to the memory-impairing effects of obesity.
authors.affiliation: Neuroscience Institute, Georgia State University, Atlanta, Georgia, USA.
authors.forename: J N
authors.initials: JN
authors.lastname: Darling
authors.forename: A P
authors.initials: AP
authors.lastname: Ross
authors.forename: T J
authors.initials: TJ
authors.lastname: Bartness
authors.forename: M B
authors.initials: MB
authors.lastname: Parent
mesh_terms: D000818:Animals; D004032:Diet; D002149:Energy Intake; D005234:Fatty Liver / Q000209:etiology* / Q000378:metabolism; D006624:Hippocampus; D050356:Lipid Metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D018782:Maze Learning; D008568:Memory; D008569:Memory Disorders / Q000209:etiology* / Q000378:metabolism; D065626:Non-alcoholic Fatty Liver Disease; D009765:Obesity / Q000378:metabolism / Q000523:psychology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015430:Weight Gain / Q000502:physiology