Biased GRK Signaling Via β2-Adrenergic Receptors in Human Skeletal Muscle

This longitudinal mechanistic physiological study examines biased β2-adrenergic receptor (β2-AR) signaling in human skeletal muscle, with emphasis on G protein-coupled receptor kinase (GRK)-mediated pathways. Participants will receive daily oral dosing of the GRK-selective long-acting β2-agonist ATR-258 for 8 weeks. Muscle biopsies and physiological measurements will quantify GRK-, cAMP/PKA-, and β-arrestin-related signaling, fiber-type specificity, and potential receptor desensitization with repeated stimulation.

NCT Number	NCT07421024
Lead Sponsor	Morten Hostrup, PhD Collaborators: Atrogi AB, University of Copenhagen, Stockholm University
Conditions	Overweight and Obesity
Enrollment	10 participants
Start Date	2026-02-20
Primary Completion	2026-12-31 (estimated)
Study Completion	2026-12-31 (estimated)
Updated on ClinicalTrials.gov	2026-02-19