title: Food access schedule and diet composition alter rhythmicity of serum melatonin and pineal NAT activity.
abstract: This study investigated the effect of dietary composition and food access schedule on the rhythmicity of serum melatonin and pineal N-acetyltransferase (NAT) activity. Wistar rats maintained on a 12:12 h light-dark cycle were assigned to two dietary groups: a group fed rat chow and a group fed a choice between a protein-rich and a carbohydrate-rich diet. Each dietary group was further divided based on feeding schedule, with food available between 0800 and 1600 h or ad lib access to food. Regardless of dietary condition, total food and carbohydrate intake of rats having free access to food was higher than under the restricted food access schedule. Protein intake of rats fed the dietary choice was lower with the restricted access than in the free access. In rats fed the dietary choice, melatonin levels and NAT activity were significantly decreased with restricted access compared to free access. Such results were not found in rats offered restricted chow. This study suggests that the rhythms of melatonin secretion and NAT activity can be altered by dietary composition.
authors.affiliation: School of Dietetics and Human Nutrition, Macdonald Campus of McGill University, 21,111 Lakeshore Road, H9X 3V9, Ste Anne de Bellevue, PQ, Canada.
authors.forename: B
authors.initials: B
authors.lastname: Selmaoui
authors.forename: A
authors.initials: A
authors.lastname: Oguine
authors.forename: L
authors.initials: L
authors.lastname: Thibault
mesh_terms: D000818:Animals; D001191:Arylamine N-Acetyltransferase / Q000502:physiology*; D001835:Body Weight / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology*; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage; D005247:Feeding Behavior / Q000502:physiology*; D008297:Male; D008550:Melatonin / Q000097:blood*; D010870:Pineal Gland / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012055:Reinforcement Schedule
chemical_list: D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D001191:Arylamine N-Acetyltransferase; D008550:Melatonin