RRC ID 27735
著者 Blevins JE, Moralejo DH, Wolden-Hanson TH, Thatcher BS, Ho JM, Kaiyala KJ, Matsumoto K.
タイトル Alterations in activity and energy expenditure contribute to lean phenotype in Fischer 344 rats lacking the cholecystokinin-1 receptor gene.
ジャーナル Am J Physiol Regul Integr Comp Physiol
Abstract CCK is hypothesized to inhibit meal size by acting at CCK1 receptors (CCK1R) on vagal afferent neurons that innervate the gastrointestinal tract and project to the hindbrain. Earlier studies have shown that obese Otsuka Long-Evans Tokushima Fatty (OLETF) rats, which carry a spontaneous null mutation of the CCK1R, are hyperphagic and obese. Recent findings show that rats with CCK1R-null gene on a Fischer 344 background (Cck1r(-/-)) are lean and normophagic. In this study, the metabolic phenotype of this rat strain was further characterized. As expected, the CCK1R antagonist, devazepide, failed to stimulate food intake in the Cck1r(-/-) rats. Both Cck1r(+/+) and Cck1r(-/-) rats became diet-induced obese (DIO) when maintained on a high-fat diet relative to chow-fed controls. Cck1r(-/-) rats consumed larger meals than controls during the dark cycle and smaller meals during the light cycle. These effects were accompanied by increased food intake, total spontaneous activity, and energy expenditure during the dark cycle and an apparent reduction in respiratory quotient during the light cycle. To assess whether enhanced responsiveness to anorexigenic factors may contribute to the lean phenotype, we examined the effects of melanotan II (MTII) on food intake and body weight. We found an enhanced effect of MTII in Cck1r(-/-) rats to suppress food intake and body weight following both central and peripheral administration. These results suggest that the lean phenotype is potentially driven by increases in total spontaneous activity and energy expenditure.
巻・号 303(12)
ページ R1231-40
公開日 2012-12-15
DOI 10.1152/ajpregu.00393.2012
PII ajpregu.00393.2012
PMID 23115121
PMC PMC3532586
MeSH Animals Body Weight / drug effects Body Weight / physiology Devazepide / pharmacology Eating / drug effects Eating / physiology Energy Metabolism / physiology* Gene Deletion Male Models, Animal Motor Activity / physiology* Peptides, Cyclic / pharmacology Phenotype* Rats Rats, Inbred F344 Rats, Mutant Strains Receptor, Cholecystokinin A / antagonists & inhibitors Receptor, Cholecystokinin A / deficiency* Receptor, Cholecystokinin A / genetics Sequence Deletion / genetics Thinness / physiopathology* alpha-MSH / analogs & derivatives alpha-MSH / pharmacology
IF 3.026
引用数 6
WOS 分野 PHYSIOLOGY
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