Endocrine Abstracts

Introduction: Craving for sweet taste is innate, and spans all ages in humans. The hedonic response to sweet taste predicts the future weight gain in humans. In this study, we investigated the association of sweet taste questionnaires (STQ) with dopamine transporter and brain glucose uptake.

Methods: Thirty-five healthy, nonobese male subjects were enrolled in this study. Each subject visited the institution three times, on separate days, for three brain PET scans (two¹⁸ F-FP-CIT PET scans and one¹⁸ F-FDG PET scan). Dynamic¹⁸ F-FP-CIT PET scans were acquired 10 mins after injection of either glucose (300 mg/kg) or placebo. Static ¹⁸ F-FDG PET scans were acquired 60 mins after injection of¹⁸ F-FDG. For¹⁸ F-FP-CIT PET, dopamine transporter (DAT) availability, expressed in terms of binding potential (BP_ND), were measured by analyzing time-activity curve via the simplified reference tissue method. For¹⁸ F-FDG PET, the mean uptake of each striatal region-of-interest was scaled to the mean of global cortical uptake of each individual, and defined as standardized uptake value ratio (SUVR). Also, subjects were assessed with 12-item self-reporting Sweet Taste Questionnaire (STQ) with 2 factors; STQ 1: sensitivity to the mood altering effect of sweets, and STQ 2: impaired control over eating sweet foods. The effects of STQ on striatal BP_NDand SUVR were investigated using Bayesian hierarchical modelling. We created models separately with STQ 1, and STQ 2 as predictors, with striatal BP_ND and SUVR as a dependent variable, adjusting for age.

Results: Thirty-five subjects (age 24.4±2.7 years, BMI 23.8±3.4 kg/m²) underwent two¹⁸ F-FP-CIT brain PET scans, and twenty-four underwent additional¹⁸ F-FDG brain PET scans. STQ 1 (sensitivity to the mood altering effect of sweets) ranged from 7 to 28 with the mean of 14.9±5.9. STQ 2 (impaired control over eating sweet foods) ranged from 5 to 19 with the mean of 9.1±4.3. Glucose-loaded DAT availability was negatively associated with STQ 1 (sensitivity to the mood altering effect of sweets), and positively with STQ 2 (impaired control over eating sweet foods). However, the effects of STQ 1 and STQ 2 on placebo-loaded DAT availability and brain glucose uptake markedly overlapped with zero.

Conclusion: Glucose-loaded dopamine transporter is associated with mood altering effect of sweet foods and control over eating sweets. The change of dopamine transporter after glucose loading may be the key role for the craving for the sweet foods.