HPA Axis Responsiveness Associates with Central Serotonin Transporter Availability in Human Obesity and Non-Obesity Controls.

Background: Alterations of hypothalamic-pituitary-adrenal (HPA) axis activity and serotonergic signaling are implicated in the pathogenesis of human obesity and may contribute to its metabolic and mental complications. The association of these systems has not been investigated in human obesity.

Objective: To investigate the relation of HPA responsiveness and serotonin transporter (5-HTT) availability in otherwise healthy individuals with obesity class II or III (OB) compared to non-obesity controls (NO).

The effect of serum BDNF levels on central serotonin transporter availability in obese versus non-obese adults: A [(11)C]DASB positron emission tomography study.

Background: Serotonin (5-HT) and its neurotrophic support system, specifically brain-derived neurotrophic factor (BDNF), are thought to modulate energy homeostasis and susceptibility to obesity. Moreover, a polymorphism (5-HTTLPR) in the serotonin reuptake transporter (5-HTT) gene impairs its transcription, thereby altering serotonergic tone and potentially contributing to such susceptibility. This study aims to investigate the effect of BDNF, biallelic 5-HTTLPR, and central in-vivo 5-HTT availability in highly obese versus non-obese subjects using positron emission tomography (PET) and 5-HTT selective [(11)C]DASB.

Central serotonin transporter availability in highly obese individuals compared with non-obese controls: A [(11)C] DASB positron emission tomography study.

Purpose: The role of the central serotonin (5-hydroxytryptamine, 5-HT) system in feeding has been extensively studied in animals with the 5-HT family of transporters (5-HTT) being identified as key molecules in the regulation of satiety and body weight. Aberrant 5-HT transmission has been implicated in the pathogenesis of human obesity by in vivo positron emission tomography (PET) and single-photon emission computed tomography (SPECT) imaging techniques. However, results obtained thus far from studies of central 5-HTT availability have been inconsistent, which is thought to be brought about mainly by the low number of individuals with a high body mass index (BMI) previously used.