Table of Contents
International Journal of Peptides
Volume 2012 (2012), Article ID 452524, 10 pages
http://dx.doi.org/10.1155/2012/452524
Research Article

Diet-Induced Obesity in Mice Overexpressing Neuropeptide Y in Noradrenergic Neurons

1Department of Pharmacology, Drug Development, and Therapeutics and Turku Center for Disease Modeling, University of Turku, Itäinen Pitkäkatu 4B, 20520 Turku, Finland
2Fin Pharma Doctorate Program Drug Discovery Section, University of Turku, Itäinen Pitkäkatu 4B, 20520 Turku, Finland
3Unit of Clinical Pharmacology, Turku University Hospital, Itäinen Pitkäkatu 4B, 20520 Turku, Finland

Received 25 May 2012; Accepted 6 September 2012

Academic Editor: Hubert Vaudry

Copyright © 2012 Suvi T. Ruohonen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Neuropeptide Y (NPY) is a neurotransmitter associated with feeding and obesity. We have constructed an NPY transgenic mouse model (OE- mouse), where targeted overexpression leads to increased levels of NPY in noradrenergic and adrenergic neurons. We previously showed that these mice become obese on a normal chow. Now we aimed to study the effect of a Western-type diet in OE- and wildtype (WT) mice, and to compare the genotype differences in the development of obesity, insulin resistance, and diabetes. Weight gain, glucose, and insulin tolerance tests, fasted plasma insulin, and cholesterol levels were assayed. We found that female OE- mice gained significantly more weight without hyperphagia or decreased activity, and showed larger white and brown fat depots with no difference in UCP-1 levels. They also displayed impaired glucose tolerance and decreased insulin sensitivity. OE- and WT males gained weight robustly, but no difference in the degree of adiposity was observed. However, 40% of but none of the WT males developed hyperglycaemia while on the diet. The present study shows that female OE- mice were not protected from the obesogenic effect of the diet suggesting that increased NPY release may predispose females to a greater risk of weight gain under high caloric conditions.