The trial design is a single-center, phase 1, open-label, exploratory study to examine the adipocyte gene expression in adults treated with 1 dose of 100mg oral mirabegron.~This is an exploratory study to examine the effects of a single dose of mirabegron on adipocytes in insulin resistant obese individuals and lean controls. Approximately 40 patients over the age of 18 will be recruited for the study (20 obese individuals with insulin resistance and 20 lean controls).~There will be a total of three study visits: Screening/Eligibility, Pre-Dose Adipose Tissue Biopsy and Post-Dose Adipose Tissue Biopsy. All visits will take place at the ACTRI research clinic at UC San Diego. The Screening/Eligibility visit will involve collection of safety data and eligibility criteria, medical/medication history, physical exam, vitals, ECG and collection of urine and blood for safety laboratory analysis. The procedures completed at the Pre-Dose visit will be, vitals, re-review of medical history and changes since last visit, indirect calorimetry, an oral glucose tolerance test (OGTT), an adipose tissue biopsy, blood sample collection and study drug dispensing (one dose to be taken the morning of the following visit). The procedures completed at the Post-Dosing visit will be identical to those completed at the Baseline visit, except there will not be an OGTT at the Post-Dosing Visit.
This study will examine the gene expression of the adrenergic Beta-3 receptor (ADRB3) regulation in human subcutaneous adipose tissue before and after treatment with mirabegron, an ADRB3 agonist. Gene expression will be compared across two groups, lean and obese participants. There will be a total of three study visits: Screening/Eligibility, Pre-Dose Adipose Tissue Biopsy and Post-Dose Adipose Tissue Biopsy. Participants will be given a single dose of 100mg oral mirabegron on the day of the Post-Dose Adipose Tissue Biopsy.The trial design is a single-center, phase 1, open-label, exploratory study to examine the adipocyte gene expression in adults treated with 1 dose of 100mg oral mirabegron.