Altered hypothalamic signaling and responses to food deprivation in rats fed a low-carbohydrate diet

Kimberly P. Kinzig, Karen A. Scott, Jayson Hyun, Sheng Bi, Timothy H. Moran

Research output: Contribution to journalArticle

Abstract

Objective: To model how consuming a low-carbohydrate (LC) diet influences food intake and body weight. Research Methods and Procedures: Food intake and body weight were monitored in rats with access to chow (CH), LC-high-fat (HF), or HF diets. After 8 weeks, rats received intracerebroventricular injections of a melanocortin agonist (melanotan-II) and antagonist (SHU9119), and feeding responses were measured. At sacrifice, plasma hormones and hypothalamic expression of mRNA for proopiomelanocortin (POMC), melanocortin-4 receptor, neuropeptide Y (NPY), and agouti related protein (AgRP) were assessed. A second set of rats had access to diet (chow or LC-HF) for 4 weeks followed by 24 h food deprivation on two occasions, after which food intake and hypothalamic POMC, NPY, and AgRP mRNA expression were measured. Results: HF rats consumed more food and gained more weight than rats on CH or LC-HF diets. Despite similar intakes and weight gains, LC-HF rats had increased adiposity relative to CH rats. LC-HF rats were more sensitive to melanotan-II and less sensitive to SHU9119. LC-HF rats had increased plasma leptin and ghrelin levels and de-creased insulin levels, and patterns of NPY and POMC mRNA expression were consistent with those of food-deprived rats. LC-HF rats did not show rebound hyperphagia after food deprivation, and levels NPY, POMC, and AgRP mRNA expression were not affected by deprivation. Discussion: Our results demonstrate that an LC diet influences multiple systems involved in the controls of food intake and body weight. These data also suggest that maintenance on an LC-HF diet affects food intake by reducing compensatory responses to food deprivation.

Original languageEnglish (US)
Pages (from-to)1672-1682
Number of pages11
JournalObesity research
Volume13
Issue number10
DOIs
StatePublished - Jan 1 2005
Externally publishedYes

Keywords

  • Ghrelin
  • Insulin
  • Ketogenic diet
  • Melanocortin-4 receptor
  • Proopiomelanocortin

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Food Science
  • Endocrinology, Diabetes and Metabolism
  • Endocrinology
  • Public Health, Environmental and Occupational Health

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