Physiology of brown fat in humans

Impact of beta-adrenergic agents, sex steroids, growth hormone and corticosteroids on brown fat activity in adult humans

Status

Not yet recruiting

Phases

Phase 2

Study type

Interventional

Source

ANZCTR

Registry ID

ACTRN12611001198910

Enrollment

Registered

2011-11-22

Start date

2012-02-01

Completion date

Unknown

Last updated

2020-01-13

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

None listed

Brief summary

The proposed study investigates the physiology of brown fat in adult humans. Brown fat plays a major role in metabolism, protecting animals from obesity. In humans, brown fat is thought to disappear after infancy. However, metabolic imaging by positron emission tomography (PET)-CT using fluorodeoxyglucose (FDG), a glucose analogue, has revealed fat of high metabolic activity in the neck region in adults, confirmed to be brown fat on histology. Our previous molecular and histological analysis suggests brown fat to be present in the majority of adult humans. However, factors regulating brown fat activity/abundance are unknown. By PET, brown fat prevalence was higher in women, associated with lower age, weight and glucose level, suggesting regulation by hormones and a role in energy homeostasis. The hypothesis of the current study is that brown fat is regulated hormonally and contributes significantly to metabolism. We aim to determine physiologic factors which regulate brown fat activity and its metabolic significance in adulthood. The proposal involves regulatory studies in-vivo (FDG uptake) to explore effects of adrenergic, sex and metabolic hormones on brown fat activity. Metabolic significance will be determined by relating FDG uptake to diet-induced thermogenesis.

Interventions

Arm 1: oral bisoprolol 2.5 mg daily for 7 days Arm 2: oral formoterol 80 ug daily for 7 days Arm 3: transdermal testosterone 50mg daily for 7 days Arm 4: oral oestradiol 50ug daily for 1 cycle Arm 5: subcutaneous growth hormone 0.5 mg daily for 7 days Arm 6: oral prednisone 10 mg daily for 7 days Subjects will be recruited into only one arm and the selection is based on the specific inclusion criteria for each arm and will be at the discretion of the investigator.

Study design

Allocation

Non-randomised trial

Intervention model

Parallel

Primary purpose

Treatment

Masking

Open (masking not used)

Eligibility

Sex/Gender

All

Age

18 Years to No maximum

Healthy volunteers

Yes

Inclusion criteria

Arms 1, 2 and 6: healthy adults 18+ years old Arm 3: men with hypogonadism Arm 4: postmenopausal women Arm 5: growth hormone deficient adults

Exclusion criteria

pregnancy

Outcome results