CJC-1295 GHRH Receptor Research Overview

CJC-1295 is a synthetic GHRH analogue incorporating Drug Affinity Complex (DAC) technology via maleimidoproprionic acid modification at Lys30, enabling covalent albumin binding for extended GHRH-R engagement in research models. A non-DAC version (Mod GRF 1-29 / CJC-1295 without DAC) provides a shorter-acting comparator for receptor kinetics research.

Molecular Properties

| Property | CJC-1295 DAC | Mod GRF 1-29 |

|----------|--------------|--------------|

| MW | 3647.3 g/mol | 3367.9 g/mol |

| CAS | 863288-34-0 | - |

| Receptor engagement | Extended (albumin-bound) | Standard pulsatile |

GHRH Receptor Pharmacology

Receptor Binding Characteristics

The growth hormone-releasing hormone receptor (GHRH-R) belongs to the class B G-protein coupled receptor family, characterized by a large N-terminal extracellular domain essential for ligand recognition. CJC-1295 demonstrates high binding affinity for GHRH-R through enhanced stability of the receptor-ligand complex. In vitro binding assays reveal sustained receptor occupancy profiles compared to native GHRH, attributed to the DAC modification preventing enzymatic degradation.

Radioligand binding studies utilizing [125I]-GHRH displacement assays show CJC-1295 maintains competitive binding kinetics with Ki values comparable to native GHRH. The albumin-binding component does not interfere with initial receptor recognition, as the active peptide sequence remains available for GHRH-R interaction following albumin association.

Signal Transduction Mechanisms

GHRH-R activation by CJC-1295 initiates canonical Gs-protein signaling cascades in somatotroph cell models. Primary signaling involves adenylyl cyclase activation, generating cyclic adenosine monophosphate (cAMP) as the principal second messenger. Elevated intracellular cAMP levels activate protein kinase A (PKA), subsequently phosphorylating cAMP response element-binding protein (CREB).

Phosphorylated CREB translocates to the nucleus, binding cAMP response elements in growth hormone gene promoter regions. This transcriptional activation increases growth hormone mRNA expression and subsequent protein synthesis in pituitary cell cultures.

In Vitro Assay Applications

Cell-Based Receptor Activity Models

Primary rat pituitary cell cultures serve as standard models for GHRH-R pharmacology research. These systems maintain physiological receptor expression patterns and downstream signaling machinery. CJC-1295 stimulation of these cultures demonstrates dose-dependent growth hormone release with EC50 values reflecting potent receptor activation.

Immortalized somatotroph cell lines, including GC and GH3 cells, provide reproducible platforms for mechanistic studies. These models enable investigation of receptor desensitization patterns, with CJC-1295 showing reduced tachyphylaxis compared to native GHRH in repeated stimulation protocols.

Enzyme Kinetics and Stability Studies

CJC-1295's enhanced stability profile results from resistance to dipeptidyl peptidase-IV (DPP-IV) and neutral endopeptidase degradation. In vitro stability assays using purified enzyme preparations demonstrate significantly extended half-life compared to unmodified GHRH analogues. The DAC modification creates steric hindrance preventing enzymatic access to susceptible cleavage sites.

Plasma stability studies reveal albumin binding kinetics following DAC-mediated covalent attachment. Surface plasmon resonance analysis shows strong albumin association with slow dissociation rates, explaining the extended pharmacokinetic profile observed in cell culture medium containing albumin.

Metabolic Pathway Integration

IGF-1 Signaling Networks

Growth hormone released following GHRH-R activation stimulates hepatocyte IGF-1 production in co-culture systems. CJC-1295 treatment of integrated pituitary-hepatocyte models demonstrates sustained IGF-1 elevation, reflecting prolonged growth hormone secretion patterns. IGF-1 receptor activation in target cell models shows enhanced downstream PI3K/Akt signaling pathway engagement.

Metabolic Enzyme Modulation

In hepatocyte culture systems, CJC-1295-stimulated growth hormone exposure modulates key metabolic enzyme activities. Gluconeogenesis pathway enzymes show altered activity profiles, while lipid metabolism pathways demonstrate enhanced β-oxidation enzyme expression. These metabolic changes reflect the integrated cellular response to sustained growth hormone signaling.

Comparative Pharmacology Studies

Research comparing CJC-1295 DAC versus non-DAC variants reveals distinct receptor engagement profiles. The DAC version maintains prolonged receptor activation in albumin-containing media, while Mod GRF 1-29 shows typical pulsatile patterns. This comparison enables investigation of sustained versus intermittent GHRH-R stimulation effects on cellular metabolism and gene expression patterns.

Research Summary

CJC-1295 represents a valuable research tool for investigating GHRH receptor pharmacology and growth hormone axis regulation. Its unique DAC modification provides extended receptor engagement through albumin binding while maintaining native receptor recognition sequences. In vitro studies demonstrate potent GHRH-R activation, canonical signaling pathway engagement, and integration with metabolic enzyme networks. The compound's stability profile and sustained activity make it particularly suitable for investigating long-term growth hormone signaling effects in cellular models, offering advantages over native GHRH in mechanistic research applications.

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