Collared lemmings are able to double their body weight and body fat content in response to a change in photoperiod. This occurs without a change in food intake. Photo-induced changes in body weight will be used to examine the temporal relationships among changes in energy expenditure (resting and activity) and fuel partitioning. In this revised application, it is proposed that both leptin and corticosterone may play important roles in the seasonal changes in body weight and body composition. It is hypothesized that during weight gain: 1) A decrease in resting energy expenditure will be associated with the early phase of weight gain, and a decrease in energy expenditure associated with physical activity will be associated with weight maintenance after weight gain; 2) increased metabolic efficiency (decreased expression of uncoupling protein mRNA) will cause the decrease in resting energy expenditure during the early phase of weight gain; 3) the photoperiod-induced decrease in corticosterone concentration will decrease ob mRNA expression, which in turn will decrease uncoupling protein mRNA expression. The converse will also be studied during weight loss in this model system. The results will shed light on the role of energy expenditure and energy partitioning on the regulation of body weight and body composition. The basic scientific information gained from this model should be useful for understanding the role of metabolic perturbations in the etiology of human obesity.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
1R01DK054918-01
Application #
2740955
Study Section
Nutrition Study Section (NTN)
Program Officer
Yanovski, Susan Z
Project Start
1998-06-01
Project End
2003-05-31
Budget Start
1998-06-01
Budget End
1999-05-31
Support Year
1
Fiscal Year
1998
Total Cost
Indirect Cost
Name
University of Alabama Birmingham
Department
Nutrition
Type
Schools of Allied Health Profes
DUNS #
004514360
City
Birmingham
State
AL
Country
United States
Zip Code
35294
Johnson, Maria S; Onorato, David P; Gower, Barbara A et al. (2004) Weight change affects serum leptin and corticosterone in the collared lemming. Gen Comp Endocrinol 136:30-6
Nagy, Tim R; Blaylock, Matthew L; Garvey, W Timothy (2004) Role of UCP2 and UCP3 in nutrition and obesity. Nutrition 20:139-44
Blaylock, Matthew L; Wang, Ruixue; Shan, Dan et al. (2004) Ucp3 expression during weight gain and loss, cold exposure, and fasting in the collared lemming. Obes Res 12:1690-7
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Powell, Charles Stephenson; Blaylock, Matthew L; Wang, Ruixue et al. (2002) Effects of energy expenditure and Ucp1 on photoperiod-induced weight gain in collard lemmings. Obes Res 10:541-50
Nagy, Tim R; Krzywanski, David; Li, Jing et al. (2002) Effect of group vs. single housing on phenotypic variance in C57BL/6J mice. Obes Res 10:412-5
Hunter, Heather L; Nagy, Tim R (2002) Body composition in a seasonal model of obesity: longitudinal measures and validation of DXA. Obes Res 10:1180-7
Gower, Barbara A; Nagy, Tim R; Blaylock, Matthew L et al. (2002) Estradiol may limit lipid oxidation via Cpt 1 expression and hormonal mechanisms. Obes Res 10:167-72
Brix, Amy E; Elgavish, Ada; Nagy, Tim R et al. (2002) Evaluation of liver fatty acid oxidation in the leptin-deficient obese mouse. Mol Genet Metab 75:219-26

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