Thyroid Releasing Hormone
Thyrotropin-Releasing Hormone (TRH)
Overview
Thyrotropin-Releasing Hormone (TRH) is a tripeptide (pyroglutamyl-histidyl-proline amide) produced by the hypothalamus that stimulates the pituitary to release thyroid-stimulating hormone (TSH) which in turn stimulates thyroid hormone production. Beyond its role in the hypothalamic-pituitary-thyroid axis TRH has demonstrated potent central nervous system effects including antidepressant activity stimulant effects and neuroprotective properties. It is used diagnostically to test pituitary and thyroid function and is being investigated for depression amyotrophic lateral sclerosis and spinal cord injury.
Mechanism of Action
TRH acts through TRH receptors (TRH-R1 and TRH-R2) coupled to Gq proteins expressed in the pituitary thyroid and throughout the brain. Pituitary TRH receptor activation stimulates both TSH and prolactin release. In the brain TRH receptors are found in limbic regions brainstem and spinal cord where TRH acts as a neuromodulator independent of its endocrine functions. Central TRH signaling has antidepressant effects — it activates monoaminergic systems increasing dopamine serotonin and norepinephrine activity. TRH also has direct neurotropic effects promoting motor neuron survival and has shown benefit in clinical trials for ALS. It antagonizes barbiturate and ethanol-induced CNS depression explaining early research interest in its analeptic (arousal-promoting) properties. The combination of thyroid axis activation and direct CNS effects makes TRH a pleiotropic neurohormone with multiple therapeutic angles.
Where does Thyroid Releasing Hormone sit?
See how this peptide compares across all 85 peptides in our database.
Dosage Information
Typical Dose
0.5-1 mg (diagnostic use), various research doses
Frequency
Single dose for diagnostic testing
Administration
Intravenous (diagnostic), intranasal (research)
Notes
Intranasal TRH is being investigated for depression and neuroprotection as a route that avoids rapid systemic metabolism. Very short half-life (5-6 minutes IV) necessitates intranasal or sustained-release formulations for therapeutic use.
Potential Side Effects
Community Experiences
No experiences shared yet. Be the first!
Quick Facts
- Administration
- Intravenous (diagnostic), intranasal (research)
- Typical Dose
- 0.5-1 mg (diagnostic use), various research doses
- Frequency
- Single dose for diagnostic testing
- References
- 0 curated + 45 from PubMed
- Clinical Trials
- 22 registered
- Evidence Score
- 62.0 / 100