Document Detail

Circadian rhythm drives the responsiveness of leptin-mediated hypothalamic pathway of cholecystokinin-8.
MedLine Citation:
PMID:  18638520     Owner:  NLM     Status:  MEDLINE    
Cholecystokinin (CCK) and leptin act coordinately in the brain to regulate food intake and energy balance. Recently we have reported that CCK enhances the permeability of brain barriers to leptin and we have proposed that CCK enhances energy expenditure in rats by activating in the hypothalamus the janus kinase/signal transducer and activator of transcription (JAK/STAT) signalling pathway, which is coupled to leptin receptors. Because plasma leptin concentration follows a circadian rhythm (plasma leptin concentration rise maximal values during the night, after rats start eating), we have hypothesized that the interaction between leptin and CCK should be more intense in animals receiving CCK during the night, i.e., during periods of positive energy balance. In order to further characterize the physiological relevance of the interplay between leptin and CCK we have compared the effect of diurnal vs. nocturnal administration of the C-terminal octapeptide of CCK (CCK-8) on (i) body weight and food intake, and (ii) STAT3 activation, by analyzing phosphorylated STAT3 (pSTAT3) immunostaining within the arcuate nucleus of the hypothalamus. Our results show that CCK decreases body weight and food intake only after p.m. administration. Accordingly pSTAT3 immunostaining within the hypothalamus was more intense in p.m. than in a.m.-treated animals. These data suggest that the effect of CCK on leptin pathways follows a circadian rhythm linked to the energy balance status and gives further support to the interaction between leptin and CCK.
Beatriz Merino; Beatriz Somoza; Mariano Ruiz-Gayo; Victoria Cano
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-07-10
Journal Detail:
Title:  Neuroscience letters     Volume:  442     ISSN:  0304-3940     ISO Abbreviation:  Neurosci. Lett.     Publication Date:  2008 Sep 
Date Detail:
Created Date:  2008-08-04     Completed Date:  2008-12-12     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7600130     Medline TA:  Neurosci Lett     Country:  Ireland    
Other Details:
Languages:  eng     Pagination:  165-8     Citation Subset:  IM    
Departamento de Farmacología, Tecnología y Desarrollo Farmacéutico, Universidad CEU-San Pablo, Urbanización Montepríncipe, Boadilla del Monte, 28668 Madrid, Spain.
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MeSH Terms
Behavior, Animal / drug effects
Body Weight / drug effects
Circadian Rhythm / physiology*
Dose-Response Relationship, Drug
Eating / drug effects
Gene Expression Regulation / drug effects,  physiology
Hypothalamus / drug effects*,  metabolism
Leptin / pharmacology*
Rats, Sprague-Dawley
STAT3 Transcription Factor / metabolism
Signal Transduction / drug effects*
Sincalide / metabolism*
Reg. No./Substance:
0/Leptin; 0/STAT3 Transcription Factor; 25126-32-3/Sincalide

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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