Biased GRK Signaling Via β2-Adrenergic Receptors in Human Skeletal Muscle (NCT07421024) | Clinical Trial Compass
Not Yet RecruitingPhase 2
Biased GRK Signaling Via β2-Adrenergic Receptors in Human Skeletal Muscle
Denmark10 participantsStarted 2026-02-20
Plain-language 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.
Who can participate
Age range
21 Years – 45 Years
Sex
MALE
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
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
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
Intensity of β2-AR downstream signaling pathways (GRK, cAMP/PKA, and β-arrestin) in type I and type II muscle fibers
Timeframe: Before and 4 hours after ATR-258 ingestion on day 1, 29, and 56.