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Decreased plasma PYY accompanied by elevated PYY and Y2 receptor binding densities in the medulla oblongata of diet-induced obese mice


Rahardjo, GL and Huang, XF and Tan, YY and Deng, C, Decreased plasma PYY accompanied by elevated PYY and Y2 receptor binding densities in the medulla oblongata of diet-induced obese mice, Endocrinology, 148, (10) pp. 4704-4710. ISSN 0013-7227 (2007) [Refereed Article]

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Copyright 2007 by The Endocrine Society

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DOI: doi:10.1210/en.2007-0107


It is well known that the peripheral peptide YY (PYY)-central neuropeptide Y (NPY) Y2 receptor axis plays an important role in promoting negative energy balance regulation. Both the hypothalamus and medulla oblongata express a high level of Y2 receptors; however, the functional role of this receptor in chronic high-fat diet-induced obesity has not been fully examined. Using quantitative autoradiography, this study measured binding densities of total [125I]PYY and Y2 receptors in the hypothalamus and medulla of chronic high-fat diet-induced obese (DIO), obese-resistant, and low-fat-fed mice. Plasma PYY was also measured using RIA after 22 wk of dietary intervention. The results revealed that body weight gain was significantly higher in the obese mice, compared with the lean mice. Furthermore, PYY and NPY Y2 receptor binding densities in the medulla of the obese mice were significantly higher, compared with the lean mice, whereas the level of plasma PYY was significantly lower in the DIO mice than the low-fat-fed mice. In conclusion, this study showed that the DIO mice had low plasma PYY, which may have caused a compensatory up-regulation of PYY and Y2 receptor densities in the medulla. A low-level response of PYY-medullary regulation to positive energy balance may have contributed to the development of high-fat diet-induced obesity in DIO mice; conversely, a normal response of this regulatory axis in the obese-resistant mice may have contributed to the maintenance of body weight while on a high-fat diet.

Item Details

Item Type:Refereed Article
Keywords:Decreased plasma PYY, elevated PYY, Y2 receptor binding densities, medulla oblongata, diet induced obese mice
Research Division:Biomedical and Clinical Sciences
Research Group:Pharmacology and pharmaceutical sciences
Research Field:Pharmacology and pharmaceutical sciences not elsewhere classified
Objective Division:Health
Objective Group:Public health (excl. specific population health)
Objective Field:Preventive medicine
UTAS Author:Tan, YY (Dr Yean Tan)
ID Code:47838
Year Published:2007
Web of Science® Times Cited:23
Deposited By:Pharmacy
Deposited On:2007-09-21
Last Modified:2010-03-01

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