title: Fructose:glucose ratios--a study of sugar self-administration and associated neural and physiological responses in the rat.
abstract: This study explored whether different ratios of fructose (F) and glucose (G) in sugar can engender significant differences in self-administration and associated neurobiological and physiological responses in male Sprague-Dawley rats. In Experiment 1, animals self-administered pellets containing 55% F + 45% G or 30% F + 70% G, and Fos immunoreactivity was assessed in hypothalamic regions regulating food intake and reward. In Experiment 2, rats self-administered solutions of 55% F + 42% G (high fructose corn syrup (HFCS)), 50% F + 50% G (sucrose) or saccharin, and mRNA of the dopamine 2 (D2R) and mu-opioid (MOR) receptor genes were assessed in striatal regions involved in addictive behaviors. Finally, in Experiment 3, rats self-administered HFCS and sucrose in their home cages, and hepatic fatty acids were quantified. It was found that higher fructose ratios engendered lower self-administration, lower Fos expression in the lateral hypothalamus/arcuate nucleus, reduced D2R and increased MOR mRNA in the dorsal striatum and nucleus accumbens core, respectively, as well as elevated omega-6 polyunsaturated fatty acids in the liver. These data indicate that a higher ratio of fructose may enhance the reinforcing effects of sugar and possibly lead to neurobiological and physiological alterations associated with addictive and metabolic disorders.
authors.affiliation: Department of Psychology, University of Guelph, Guelph, ON N1G 2W1, Canada. alevy01@uoguelph.ca.
authors.forename: AnneMarie
authors.initials: A
authors.lastname: Levy
authors.affiliation: Department of Psychology, University of Guelph, Guelph, ON N1G 2W1, Canada. pmarshal@uoguelph.ca.
authors.forename: Paul
authors.initials: P
authors.lastname: Marshall
authors.affiliation: Laboratory of Addictive Diseases, Rockefeller University, New York, NY 10065, USA. zhouya@mail.rockefeller.edu.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Laboratory of Addictive Diseases, Rockefeller University, New York, NY 10065, USA. Mary.Jeanne.Kreek@rockefeller.edu.
authors.forename: Mary Jeanne
authors.initials: MJ
authors.lastname: Kreek
authors.affiliation: Department of Psychology, University of Guelph, Guelph, ON N1G 2W1, Canada. katekent15@gmail.com.
authors.forename: Katrina
authors.initials: K
authors.lastname: Kent
authors.affiliation: Department of Psychology, University of Guelph, Guelph, ON N1G 2W1, Canada. daniels@uoguelph.ca.
authors.forename: Stephen
authors.initials: S
authors.lastname: Daniels
authors.affiliation: Department of Psychology, University of Guelph, Guelph, ON N1G 2W1, Canada. shorea@mail.uoguelph.ca.
authors.forename: Ari
authors.initials: A
authors.lastname: Shore
authors.affiliation: Department of Psychology, University of Guelph, Guelph, ON N1G 2W1, Canada. tianadowns@hotmail.com.
authors.forename: Tiana
authors.initials: T
authors.lastname: Downs
authors.affiliation: Department of Psychology, University of Guelph, Guelph, ON N1G 2W1, Canada. mariafer@uoguelph.ca.
authors.forename: Maria Fernanda
authors.initials: MF
authors.lastname: Fernandes
authors.affiliation: Department of Human Health & Nutritional Science, University of Guelph, Guelph, ON N1G 2W1, Canada. dmutch@uoguelph.ca.
authors.forename: David M
authors.initials: DM
authors.lastname: Mutch
authors.affiliation: Department of Psychology, University of Guelph, Guelph, ON N1G 2W1, Canada. fleri@uoguelph.ca.
authors.forename: Francesco
authors.initials: F
authors.lastname: Leri
mesh_terms: D000818:Animals; D016739:Behavior, Addictive / Q000209:etiology; D001921:Brain / Q000187:drug effects*; D004040:Dietary Carbohydrates / Q000009:adverse effects / Q000494:pharmacology*; D019422:Dietary Sucrose / Q000494:pharmacology; D004435:Eating / Q000187:drug effects*; D002149:Energy Intake / Q000187:drug effects*; D043371:Fatty Acids, Omega-6 / Q000378:metabolism; D005247:Feeding Behavior / Q000187:drug effects*; D005632:Fructose / Q000008:administration & dosage / Q000494:pharmacology*; D005947:Glucose / Q000008:administration & dosage / Q000494:pharmacology*; D066248:High Fructose Corn Syrup / Q000494:pharmacology; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009765:Obesity / Q000209:etiology; D012333:RNA, Messenger / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D017448:Receptors, Dopamine D2 / Q000235:genetics / Q000378:metabolism; D017450:Receptors, Opioid, mu / Q000235:genetics / Q000378:metabolism; D012201:Reward
chemical_list: D004040:Dietary Carbohydrates; D019422:Dietary Sucrose; D043371:Fatty Acids, Omega-6; D066248:High Fructose Corn Syrup; C485765:Oprm1 protein, rat; D012333:RNA, Messenger; D017448:Receptors, Dopamine D2; D017450:Receptors, Opioid, mu; D005632:Fructose; D005947:Glucose
keywords: dopamine 2 receptor; fatty acid; fructose; glucose; hepatic; hypothalamus; mu opioid receptor; nucleus accumbens; rat; self-administration