The Physiological Responses and Adaptation of Brown Adipose Tissue to Chronic Treatment With Beta3-Adrenergic Receptor Agonists
Eligible age
18–40 yrs
Accepts
All genders
Locations
1 state
Healthy volunteers
No
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About this study
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.
Sponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
You may not qualify if…
- ✕ 1. Hypersensitivity and associated allergic reactions to mirabegron (or similar drug substances or components)
- ✕ 2. Abnormal bladder function, diagnosis of bladder outlet obstruction, urinary incontinence, urgency, and urinary frequency or use of antimuscarinic medication to treat overactive bladder (OAB)
- ✕ 3. Type 1 or Type 2 Diabetes mellitus, fasting serum glucose \>125 mg/dL, and/or an HbA1c test \>6.5%
- ✕ 4. Hypertension, defined as blood pressure (Bullet)140/90 mmHg, based on WHO guidelines (https://www.who.int/news-room/fact-sheets/detail/hypertension)
- ✕ 5. Hypo- or hyper-thyroid disease (TSH \>5.0, \<0.4 miU/L) that is controlled for less than one year
- ✕ 6. Anemia, defined by hemoglobin \< 11.3 g/dL (females) or \< 13.8 g/dL (males); sickle cell anemia or other blood disorders; and/or wound healing problems
- ✕ 7. Cardiovascular disease, cardiac arrhythmias, orthostasis, unstable vasomotor system, or renal impairment
- ✕ 8. A clinically significant abnormal ECG and/or QTc interval above normal
Where it's recruiting
Bethesda
Source: ClinicalTrials.gov · NCT03049462 · last updated 2026-06-01