CJC-1295 (No DAC)

CJC-1295 without DAC, often written as modified GRF (1-29), is the 29-residue growth hormone-releasing hormone fragment carrying the four amino-acid substitutions of the CJC-1295 backbone but none of the maleimide group that lets the DAC version conjugate covalently to serum albumin. Without that albumin anchor it circulates as a free peptide. The 1-29 fragment is the shortest N-terminal segment of the 44-residue native factor that retains full activity, and it acts at the pituitary GHRH receptor, a G protein-coupled receptor related to the secretin and vasoactive intestinal peptide receptors.

CJC-1295 (No DAC) in the research literature

The substituted backbone comes from work on albumin-binding GRF analogs, which described CJC-1295 as a tetrasubstituted form of GRF(1-29); in that study the albumin conjugate, not the free peptide, was the source of the extended plasma persistence, while the base peptide remained the reference compound in the growth hormone secretion assay on cultured rat anterior pituitary cells.

Substituted GRF(1-29) analogs have been characterised separately. GRF(1-29)-NH2 itself was equipotent with GRF(1-44)-NH2 in a rat pituitary bioassay and retained full receptor-binding affinity, and the single-substitution analog [Ala15]-GRF(1-29)-NH2 was described as superactive in the same assay. The cloned GHRH receptor binds the releasing factor with high affinity and raises intracellular cAMP, which is the signalling step these analogs engage.