CJC-1295 vs ipamorelin: two molecules, two receptors
CJC-1295 and ipamorelin are both described as growth-hormone secretagogues, yet the literature places them at two different receptors.[1],[2]
CJC-1295 is a modified growth-hormone-releasing factor (1-29) built to attach to serum albumin, while ipamorelin is a five-residue peptide from a chemistry series based on growth-hormone-releasing peptides.[3],[4]
This page records how the two differ in structure and receptor pathway and reports no study outcome for either.
Identity side by side
| Attribute | CJC-1295 | Ipamorelin |
|---|---|---|
| Also recorded as[1],[2] | CJC-1295 with DAC; DAC:GRF | NNC 26-0161 |
| Structural basis[3],[2] | Tetrasubstituted human GRF(1-29) with an added Nε-3-maleimidopropionamide lysine at the C-terminus | Aib-His-D-2-Nal-D-Phe-Lys-NH2 |
| Length[3],[2] | Built on the 29-residue GRF(1-29) chain | 5 residues |
| CAS Registry Number[2] | Not recorded (unverified for either CJC-1295 form) | 170851-70-4 |
| Chemical lineage[1],[5],[4] | Growth-hormone-releasing hormone analogue | Series lacking the central Ala-Trp dipeptide of GHRP-1 |
| Receptor recorded[1],[2] | Growth-hormone-releasing hormone receptor | GHRP-type (growth-hormone secretagogue) receptor |
| Receptor evidence[3],[4] | Albumin conjugates activate the GRF receptor on rat anterior pituitary | GHRP and GHRH antagonist profiling pointed to a GHRP-like receptor |
| Serum albumin attachment[3],[2] | Maleimide group designed to react with albumin cysteine 34 | None recorded |
How do the two structures differ?
CJC-1295 starts from the first 29 residues of human growth-hormone-releasing factor, carries four substitutions, and adds a lysine bearing a 3-maleimidopropionamide group at the C-terminus.[3]
That maleimide is meant to react with the free thiol on cysteine 34 of serum albumin, and in rat plasma a CJC-1295-immunoreactive species was found on the albumin band.[3]
Ipamorelin is far smaller and includes three non-standard building blocks: 2-aminoisobutyric acid, D-2-naphthylalanine and D-phenylalanine.[2]
It came out of a growth-hormone-releasing peptide chemistry programme, from a series of compounds lacking the central Ala-Trp dipeptide of GHRP-1.[4]
Which receptor does each act through?
The GHRH receptor was cloned from pituitary in 1992 as a seven-transmembrane receptor related to the secretin and vasoactive intestinal peptide receptors.[6]
Albumin conjugates of the CJC-1295 series were reported to activate this GRF receptor on the anterior pituitary in rats.[3]
Ipamorelin's growth-hormone-releasing activity was traced, using GHRP and GHRH antagonists, to a GHRP-like receptor and not to the GHRH receptor.[4]
A G protein-coupled receptor of pituitary and hypothalamus that is the target of the growth-hormone secretagogue class was cloned in 1996, and the library records ipamorelin's target as this GHRP-type receptor.[7],[2]
What does the literature not compare?
No publication cited here studied CJC-1295 and ipamorelin in the same experiment.[3],[5],[4]
The published figures for each compound come from different species, designs and endpoints, and none is set against the other on this page.[5],[4],[8]
Limitations
A shared label such as growth-hormone secretagogue groups molecules by one downstream hormone; the receptor records show the two do not share an entry point.[1],[2]
The CJC-1295 receptor and albumin findings come from rat tissue and rat plasma, and ipamorelin's receptor profiling comes from rat cells and animals.[3],[4]
Compound profiles
References
- CJC-1295 research profile, PepGenex Science (identity and records, with their sources).
- Ipamorelin research profile, PepGenex Science (identity and records, with their sources).
- Jetté L, Léger R, Thibaudeau K, et al. Human growth hormone-releasing factor (hGRF)1-29-albumin bioconjugates activate the GRF receptor on the anterior pituitary in rats: identification of CJC-1295 as a long-lasting GRF analog. Endocrinology. 2005;146(7):3052-3058. PMID 15817669 · DOI 10.1210/en.2004-1286
- Raun K, Hansen BS, Johansen NL, et al. Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol. 1998;139(5):552-561. PMID 9849822 · DOI 10.1530/eje.0.1390552
- Teichman SL, Neale A, Lawrence B, et al. Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults. J Clin Endocrinol Metab. 2006;91(3):799-805. PMID 16352683 · DOI 10.1210/jc.2005-1536
- Mayo KE. Molecular cloning and expression of a pituitary-specific receptor for growth hormone-releasing hormone. Mol Endocrinol. 1992;6(10):1734-1744. PMID 1333056 · DOI 10.1210/mend.6.10.1333056
- Howard AD, Feighner SD, Cully DF, et al. A receptor in pituitary and hypothalamus that functions in growth hormone release. Science. 1996;273(5277):974-977. PMID 8688086 · DOI 10.1126/science.273.5277.974
- Beck DE, Sweeney WB, McCarter MD; Ipamorelin 201 Study Group. Title withheld on this site (see the publication record). International Journal of Colorectal Disease 2014. PMID 25331030 · DOI 10.1007/s00384-014-2030-8