title: Carbohydrate-to-fat ratio affects food intake and body weight in Wistar rats.
abstract: The aim of the study was to evaluate the impact of carbohydrate-to-fat ratio on body weight and appetite regulation in Wistar rats. Twenty-four Wistar rats were randomized to three dietary groups (n = 8): normal carbohydrate diet (NC), low-carbohydrate diet (LC) and high-carbohydrate diet (HC) for 12 weeks. Body weight and food intake were recorded. Circulating leptin and insulin levels were measured by radioimmunoassay method. The expression levels of leptin receptor, insulin receptor, orexin, neuropeptide Y (NPY), agouti-related protein (AgRP) and melanocortin-4 receptor (MC-4R) in the hypothalamus were also measured by realtime polymerase chain reaction (PCR). In the LC group, food intake reduced while body weight increased significantly compared with the NC and HC groups. Plasma leptin levels increased in the LC (18.5 +/- 8.2 ng/mL) group compared with the NC (8.6 +/- 3.8 ng/mL, P < 0.001) and HC (6.6 +/- 1.9 ng/mL, P < 0.001) groups. Realtime reverse transcription-PCR revealed a decrease in the hypothalamic expression level of only leptin receptor in the LC (0.764, 0.471-4.648 copy/mL) and HC (0.357, 0.129-0.781 copy/mL) groups compared with the NC (1.323, 0.616-2.392 copy/mL; P = 0.01) group, and that there was no significant change in those of insulin receptor, AgRP, Orexin, NPY and MC-4R. Low-carbohydrate, high-fat diet raised body weight, which led to a rising of circulating leptin levels and a reduced expression of leptin receptor in the hypothalamus.
authors.affiliation: Department of Clinical Nutrition, Ren Ji Hospital and Xin Hua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Ren-Ying
authors.initials: RY
authors.lastname: Xu
authors.forename: Yan-Ping
authors.initials: YP
authors.lastname: Wan
authors.forename: Qing-Ya
authors.initials: QY
authors.lastname: Tang
authors.forename: Jiang
authors.initials: J
authors.lastname: Wu
authors.forename: Wei
authors.initials: W
authors.lastname: Cai
mesh_terms: D054369:Agouti-Related Protein / Q000032:analysis; D000818:Animals; D001069:Appetite Regulation / Q000502:physiology*; D001835:Body Weight / Q000502:physiology*; D004040:Dietary Carbohydrates / Q000494:pharmacology*; D004041:Dietary Fats / Q000494:pharmacology*; D004435:Eating / Q000502:physiology; D007031:Hypothalamus / Q000737:chemistry; D007328:Insulin / Q000097:blood; D047908:Intracellular Signaling Peptides and Proteins / Q000032:analysis; D020738:Leptin / Q000097:blood; D008297:Male; D009478:Neuropeptide Y / Q000032:analysis; D009479:Neuropeptides / Q000032:analysis; D000068797:Orexins; D016133:Polymerase Chain Reaction; D051381:Rats; D017208:Rats, Wistar / Q000378:metabolism / Q000502:physiology; D011972:Receptor, Insulin / Q000032:analysis; D044105:Receptor, Melanocortin, Type 4 / Q000032:analysis; D054411:Receptors, Leptin / Q000032:analysis
chemical_list: D054369:Agouti-Related Protein; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D007328:Insulin; D047908:Intracellular Signaling Peptides and Proteins; D020738:Leptin; D009478:Neuropeptide Y; D009479:Neuropeptides; D000068797:Orexins; D044105:Receptor, Melanocortin, Type 4; D054411:Receptors, Leptin; D011972:Receptor, Insulin