Brown Adipose Tissue and Body Burning Energy

Physiological Responses and Adaptation of Brown Adipose Tissue to Chronic Treatment With Beta 3-Adrenergic Receptor Agonists

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: Healthy 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. ...

Pharmaceutical medication involved
Patients and healthy individuals accepted

Drug - Mirabegron

Women will take 100mg daily for 4 weeks. Men will take 200mg daily for 4 weeks. The medication is available in 50 mg tablets.

B Complex Plus Vitamin C Tablets

Males will be randomized to take placebo versus active drug (mirabegron). Those taking placebo will take 4 tablets each day to mirror to active group (taking 4 tablets of 50 mg each).

The Physiological Responses and Adaptation of Brown Adipose Tissue to Chronic Treatment With Beta-3-Adrenergic Receptor Agonists