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The effect of food access schedule and diet composition on the rhythmicity of serum melatonin and pineal N-acetyltransferase activity in rats /

Melatonin is a hormone secreted by the pineal gland, which is known to modulate biological rhythms in mammals. This study investigated the effect of food access schedule and dietary composition on serum melatonin and pineal NAT activity in adult male Wistar rats. These rats were maintained on a 12:12 h light:dark schedule with lights on at 0800h. The rats were randomly assigned to two dietary groups. A group was simultaneously fed a protein-rich and carbohydrate-rich granulated diet and the other group fed granulated rat chow. Each dietary group was further divided based on dietary feeding schedules. Animals were fed between 0800--1600 h or fed ad libitum. The study revealed that protein intake of rats fed the dietary choice was lower with the restricted access than in the free access. In rats fed dietary choice, the nocturnal melatonin levels and pineal NAT activity were significantly lower under the restricted access feeding when compared to the ad libitum feeding schedule. This was not observed in rats fed single chow diet. In conclusion our data demonstrate that food composition does affect the nocturnal synthesis of melatonin as well as the activity of the enzyme NAT. This could be via dietary intake of tryptophan, which is a precursor melatonin synthesis in the pineal gland.

Identiferoai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.33816
Date January 2002
CreatorsOguine, Adaora.
ContributorsThibault, L. (advisor)
PublisherMcGill University
Source SetsLibrary and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada
LanguageEnglish
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation
Formatapplication/pdf
CoverageMaster of Science (School of Dietetics and Human Nutrition.)
RightsAll items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated.
Relationalephsysno: 001873918, proquestno: MQ78933, Theses scanned by UMI/ProQuest.

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