Mirabegron

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. ...

This study is an exploratory study, and all the drugs involved are listed drugs. The dosage of mirabetron is selected according to the basis of previous research. The clinical recommend dose of this product is 50mg/day, and the dose used in this study is 100mg/day, which is larger than the clinical commonly used dose. The main adverse reactions of this product are urinary tract infection and rapid heartbeat. In the clinical study, we will focus on the urine routine and heart-related adverse events of the subjects, and deal with the adverse events in time. Subjects were given mirabeeron 100mg/day orally once a day in the morning until disease progression. When there are related or possible related side effects of the study drug mirabeeron, and according to NCI-CTCAE V 5.0, when subjects have more than or equal to grade 3 related toxicity, the administration should be delayed until grade 2 or lower to baseline, and the dose will be reduced by 50%, and subsequent dose increase is not allowed. If the pre-dose criteria are not met within 28 days, the drug will be permanently discontinued.