Clinical trial
Biased GRK Signaling Via β2-Adrenergic Receptors in Human Skeletal Muscle
Opening soon · Phase 2 · 1 countries · Registry ID NCT07421024
Opening soonPhase 2Interventional
What this study is about
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.
A promising-looking record is not the same as confirmed eligibility. The study team must review the full criteria and current recruitment status.
Basic eligibility
Age21 Years to 45 Years
SexMale
Healthy volunteersAccepted
ConditionOverweight and Obesity
Full registry 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
Treatments and study arms
ATR-258
Drug
Daily oral ATR-258 for 8 weeks with repeated experimental assessment days (Days 1, 15, 29, 56).
Primary outcomes
Intensity of β2-AR downstream signaling pathways (GRK, cAMP/PKA, and β-arrestin) in type I and type II muscle fibersBefore and 4 hours after ATR-258 ingestion on day 1, 29, and 56.
Assessed in vastus lateralis biopsies at rest