Dopamine and Insulin Resistance

Summary

Obese individuals have fewer striatal dopamine type 2 receptors (DRD2) than normal weight individuals. Lower DRD2 levels are associated with addiction and a decreased sense of pleasure.Obesity is also associated with insulin resistance (poor insulin action).We propose that insulin resistance and low DRD2 are associated. Using PET imaging,we aim to determine DRD2 binding potential (BP) in the brain is associated with insulin resistance and neuroendocrine hormone levels. Obese participants will be compared to lean, gender and age similar participants. We also aim to determine the effect of caloric restriction on DRD2 BP in obese subjects

Conditions

• Obesity

Interventions

RADIATION

PET scan

Both lean and obese undergo a PET scan of the brain using the radioligand,fallypride \[18F\] at baseline. Obese subjects who complete caloric restriction will have repeat scan after diet. Completed at baseline and post-VLCD

PROCEDURE

Oral glucose tolerance test

Subjects will be required to drink a glucose solution; blood samples will be taken over a 5-hour time period Completed at baseline by both lean and obese and in obese post-VLCD

PROCEDURE

MRI

An MRI of the brain and abdomen will be performed prior to PET scan One time at baseline in both lean and obese

BEHAVIORAL

Psychological scales to assess attitudes and behaviors related to eating and quality of life

A series of short psychological scales will be administered during the study. Completed at baseline

OTHER

Caloric Restriction

Obese participants only complete a short-term (\~10days) very low calorie diet

Sponsors & Collaborators

• Vanderbilt University

  lead OTHER

Principal Investigators

• Julia P Dunn, MD · Vanderbilt University Medical Center

• Robert M Kessler, MD · Vanderbilt University Medical Center

Study Design

Allocation

NON_RANDOMIZED

Purpose

OTHER

Masking

NONE

Model

SEQUENTIAL

Eligibility

Min Age

18 Years

Max Age

60 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2008-12-31

Primary Completion

2011-04-30

Completion

2012-12-31

Countries

• United States

Study Locations