CJC-1295 with DAC Mechanism of Action
Part of the full CJC-1295 with DAC guide - a synthetic growth-hormone-releasing hormone reference compound, identity-verified with a COA on every vial.
In brief
CJC-1295 with DAC is a synthetic growth-hormone-releasing hormone (GHRH/GRF) analog whose receptor behavior is dictated by a GRF(1-29) backbone fused to an albumin-binding Drug Affinity Complex. At the molecular level its activity is best understood as two coupled events: a ligand-receptor recognition step at the growth-hormone-releasing-hormone receptor (GHRHR) and a separate covalent conjugation step that tethers the peptide to circulating albumin. The receptor arm engages a class-B, secretin-family Gs-coupled GPCR expressed on pituitary somatotroph cells; the conjugation arm exploits a maleimide chemistry directed at a single albumin thiol. This spoke unpacks the signal-transduction cascade those two events set in motion in vitro, from Gs coupling through adenylate cyclase, cyclic AMP, protein kinase A, and CREB to growth-hormone gene transcription. All description below is confined to receptor coupling and conjugation chemistry as characterized in laboratory and preclinical contexts, not to any clinical or therapeutic endpoint.
The detail
A closer look
01
GHRHR engagement and Gs/adenylate-cyclase coupling
The GRF(1-29) segment of CJC-1295 acts as a ligand for the growth-hormone-releasing-hormone receptor (GHRHR), a class-B secretin-family G-protein-coupled receptor on pituitary somatotrophs documented in the Halmos et al. 2025 review (PMID 39934495). Class-B GPCRs recognize peptide ligands through a two-domain mechanism in which the extended peptide N-terminus inserts into the transmembrane core after the C-terminal portion docks to the receptor's extracellular domain. Productive binding favors a receptor conformation that couples to the stimulatory Gs heterotrimeric protein. Gs activation stimulates membrane adenylate cyclase, the committed catalytic step that converts ATP into the second messenger cyclic AMP. Because this is the receptor-recognition arm of the molecule, the four backbone substitutions do not abolish GHRHR engagement; they instead protect the same backbone from proteolysis, allowing receptor coupling to be studied in stability-extended form in vitro.
02
cAMP to PKA to CREB transcriptional output
Rising intracellular cyclic AMP activates protein kinase A (PKA) by binding its regulatory subunits and releasing active catalytic subunits. PKA phosphorylates the CREB transcription factor, which, working alongside the somatotroph-specific factor Pit-1, modulates growth-hormone gene transcription. The entry also notes an accompanying increase in intracellular calcium, consistent with the established somatotroph cascade in which cAMP/PKA signaling and calcium influx jointly drive hormone synthesis and release. In the in-vitro models referenced here, this defines a coherent GHRHR -> Gs -> adenylate cyclase -> cAMP -> PKA -> CREB/Pit-1 axis. The signal is a receptor-driven secretagogue effect: the molecule does not supply growth hormone itself but amplifies the somatotroph's own transcriptional and secretory machinery, which is why pulsatile output can be preserved in the cited physiological models rather than flattened.
03
The DAC conjugation chemistry as a distinct mechanism
Separate from receptor signaling, the defining DAC feature is a chemical one. A C-terminal Lys30 carries an Nepsilon-maleimidopropionyl linker, and the maleimide group reacts selectively with the single free thiol of cysteine-34 on serum albumin. This forms a stable thioether bioconjugate at 1:1 loading, with the cited chemistry (Leger et al. 2004, PMID 15357960) describing roughly 1000-fold accelerated reactivity toward that thiol versus other thiols. The four backbone substitutions, D-Ala2, Gln8, Ala15, and Leu27, additionally reduce susceptibility to dipeptidyl-peptidase-IV and other proteolytic cleavage in vitro. Mechanistically, then, the molecule is bifunctional: the GRF backbone supplies GHRHR agonism while the maleimide-Lys30 cap supplies covalent, site-selective albumin tethering. That tethering, not any change to the receptor cascade, is the structural basis for the molecule's extended plasma residence reported in pharmacokinetic studies.
The fine print: products are sold for laboratory research use only and are not for human or animal consumption. Bodily introduction into humans or animals is strictly prohibited by law. CJC-1295 with DAC is not a drug and is not intended to diagnose, treat, cure, or prevent any disease. These statements have not been evaluated by the FDA.