Activation of Cervical and Upper Thoracic Brown Adipose Tissue in Humans Via Beta-adrenergic Stimulation

Inclusion Criteria: healthy group * Males aged 20 - 40 years * Free of overt coronary disease (on history, medical examination and ECG) * Fasting plasma glucose \< 6.1 mmol/L and 2 hour OGTT glucose \< 7.8 mmol/L * Unmedicated * No major illness * BMI 18 - 25 Inclusion Criteria: obese group * Males aged 20 - 40 years * Free of overt coronary disease (on history, medical examination and ECG) * Unmedicated * No major illness * BMI 30+ * Weight \< 100 kg * Height \< 185 cm The inclusion criteria (Obese participants) of body weight less than \~100 kg is implemented as the PET-CT scanner to be utilised (protocol described subsequently) has a limited patient volume. Therefore to fit within the criteria of BMI \> 30, only patients of height \~183 cm or less can be recruited, and inclusion of borderline participants will be discussed with co-investigators from the Alfred Hospital Nuclear Medicine Department. Exclusion Criteria: healthy group * Unable to give informed consent * Smokers * Lactose intolerance Exclusion Criteria: obese group * Unable to give informed consent * Smokers * Lactose intolerance * Participant in research projects involving ionising radiation within the past 5 years * claustrophobia