Obesity and type 2 diabetes mellitus (T2DM) are worldwide epidemics and the mechanisms that lead from obesity to abnormal glucose homeostasis remain elusive. Accumulating evidence suggests that the neurons within the hypothalamus that sense peripheral nutrients and hormones to regulate food intake also regulate glucose homeostasis. This raises the possibility that CNS mechanisms could link obesity and T2DM. Glucagon-like peptide-1 (GLP-1), secreted by the intestine, is a potent stimulus for insulin secretion and is essential for normal glucose homeostasis. Several long-acting GLP-1 analogs have recently been developed for the treatment of T2DM. These new GLP-1 based drugs are presumed to work directly on the pancreatic 2- cell to promote insulin release. However, GLP-1 is also made in the brain, with receptors in several key regions implicated in the control of food intake and glucose homeostasis. Our preliminary data indicate that GLP-1 signaling within the hypothalamus regulates peripheral glucose levels and that the ability of CNS GLP-1 to regulate both glucose levels and food intake is dependent on glucose availability. In the 2-cell, the ability of GLP-1 to induce insulin secretion is dependent on elevated ambient glucose concentrations, a key control for homeostatic regulation. Glucokinase (GK) has been proposed to function as a glucose sensor, and we propose that the ability of central GLP-1 to regulate energy and glucose homeostasis is dependent upon glucose availability and that this in turn is regulated via GK. Specifically, the goals of this proposal are to determine which populations of GLP-1r within the CNS are linked to GK function and glucose sensing in regulation of both food intake and glucose homeostasis. The long term goals of this proposal are to elucidate specific cellular and neuronal mechanisms that link obesity to type 2 diabetes mellitus.

Public Health Relevance

Obesity and type 2 diabetes mellitus (T2DM) are worldwide epidemics and the mechanisms that lead from obesity to abnormal glucose homeostasis remain elusive. Accumulating evidence suggests that the neurons within the hypothalamus of the brain that sense peripheral nutrients and hormones to regulate food intake also regulate glucose homeostasis. The goals of this proposal are to determine the link between GLP-1 regulation of food intake and glucose homeostasis and glucose sensing within the CNS.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK082480-03
Application #
8235945
Study Section
Neuroendocrinology, Neuroimmunology, and Behavior Study Section (NNB)
Program Officer
Hyde, James F
Project Start
2010-04-15
Project End
2015-02-28
Budget Start
2012-03-01
Budget End
2013-02-28
Support Year
3
Fiscal Year
2012
Total Cost
$326,015
Indirect Cost
$118,362
Name
University of Cincinnati
Department
Psychiatry
Type
Schools of Medicine
DUNS #
041064767
City
Cincinnati
State
OH
Country
United States
Zip Code
45221
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