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

Sex: Male

Ages: 21 Years – 45 Years

Healthy volunteers: Yes

Phase: PHASE2

Enrollment: 13

Sponsor: Morten Hostrup, PhD

Location: University of Copenhagen, August Krogh Section for Human & Molecular Physiology Copenhagen

Summary

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 along with functional read-outs, tissue distribution, cardiovascular response and tolerability.

Eligibility Criteria

Inclusion Criteria: * Healthy men * Age 21-45 years * BMI 25-35 kg/m\^2 * Body fat percentage 25-40% * Lean Mass Index 14-22 Exclusion Criteria: * Regular use of or allergy to β2-agonists * Serious adverse reactions to β2-agonists * Current smoker * Regular use of medication (except OTC allergy or analgesics) * Abnormal ECG before or after β2-AR stimulation * Hypertension * Reduced kidney function (eGFR \< 90 ml/min/1.73m\^2) * Cardiovascular, metabolic, gastrointestinal, renal, or pulmonary disease * Psychiatric or neurological disorders affecting compliance/safety reporting * Cancer history within the last 5 years * Substance abuse or alcohol intake \>14 units/week

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View on ClinicalTrials.gov

Source: ClinicalTrials.gov (NCT07421024). StuddyBuddy aggregates publicly available trial information.