Actively Recruiting
The Physiological Responses and Adaptation of Brown Adipose Tissue to Chronic Treatment With Beta3-Adrenergic Receptor Agonists
Led by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) · Updated on 2026-05-12
100
Participants Needed
1
Research Sites
498 weeks
Total Duration
On this page
AI-Summary
What this Trial Is About
Background: Brown adipose tissue (BAT) is a type of fat in the body. It may prevent weight gain, improve insulin sensitivity, and reduce fatty liver. Researchers want to see if BAT helps the body burn energy. Objective: To learn more about how BAT works to burn energy. Eligibility: People ages 18-40 with a body mass index between 18 and 40 Design: Participants will be screened with: Medical history Physical exam Blood, urine, and heart tests Dietitian interview Participants will have an overnight baseline visit. This includes: Repeats of screening tests Exercise test Scans. For one scan, a radioactive substance is injected into the arm. FSIVGIT: An IV is inserted into veins in the right and left arms. Glucose and insulin are injected in one arm. Blood glucose and insulin levels are measured from the other. Metabolic suite: Participants stay 18-19 hours in a room that measures their metabolic rate. Monitors on the body measure heart rate, movement, and temperature. Optional fat biopsy: A small piece of tissue is removed with a needle. Participants will take 2-4 pills daily for 4 weeks. All women will take the drug mirabegron. Men will be randomly get either the drug or a placebo. All participants will have a visit after 2 weeks of the pills. They will repeat the screening tests. Participants will have an overnight visit 2 weeks later. They will repeat the baseline tests. Participants will keep food and medication diaries. Participants will have a follow-up visit 2 weeks after stopping the pills. This includes heart tests.
CONDITIONS
Official Title
The Physiological Responses and Adaptation of Brown Adipose Tissue to Chronic Treatment With Beta3-Adrenergic Receptor Agonists
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Female or male aged 18 to 40 years depending on cohort
- Body mass index between 18.00 and 40.0 kg/m2 for cohorts 1 and 2
- For cohort 3 females, BMI between 25.0 and 50.0 kg/m2 or BMI over 18.5 kg/m2 with PCOS diagnosis
- Diagnosis of PCOS for cohort 3 women based on NIH criteria including signs of hyperandrogenism and ovulation issues
- Women of childbearing potential must agree to use highly effective birth control for at least 3 months before and during the study
- Women not of childbearing potential must be permanently sterilized or postmenopausal for at least 12 months
- Insulin resistance defined by specific HOMA-IR scores or fasting insulin levels
- Ability to understand the research and willing to sign informed consent
You will not qualify if you...
- Allergic reactions or hypersensitivity to mirabegron or similar drugs
- Abnormal bladder function or use of medications for overactive bladder
- Type 1 or Type 2 diabetes, fasting glucose over 125 mg/dL or HbA1c over 6.5%
- Hypertension defined as blood pressure over 140/90 mmHg
- Thyroid disease uncontrolled for less than one year
- Anemia below specified hemoglobin levels or blood disorders
- Cardiovascular disease, arrhythmias, unstable vasomotor system, or kidney impairment
- Abnormal ECG or prolonged QTc interval
- Elevated liver enzymes with probable or diagnosed liver disease (except fatty liver)
- Untreated psychological conditions incompatible with study participation
- Recent infections requiring antibiotics within 4 weeks
- Intolerance to cold preventing time in cooled environment
- Current use of drugs with major interactions with mirabegron or affecting glucose metabolism
- Weight changes over 5% in the last 6 months
- Pregnancy, recent childbirth, or breastfeeding within 12 months
- Excessive outdoor exposure affecting BAT activity
- Substance addiction within last 5 years
- High daily alcohol consumption or current tobacco use
- Participation in another clinical trial with investigational or marketed drug within 2 months
- Recent or planned radiation exposure exceeding research limits
- Blood donation within last 2 months
- Unwillingness or inability to eat metabolic meals
- Any other condition that would make participation unsafe as judged by the investigator
AI-Screening
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Trial Site Locations
Total: 1 location
1
National Institutes of Health Clinical Center
Bethesda, Maryland, United States, 20892
Actively Recruiting
Research Team
A
Ashley M Schmitz, C.R.N.P.
CONTACT
A
Aaron M Cypess, M.D.
CONTACT
How is the study designed?
Study Type
INTERVENTIONAL
Masking
QUADRUPLE
Allocation
RANDOMIZED
Model
PARALLEL
Primary Purpose
BASIC_SCIENCE
Number of Arms
5
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