This is a working overview of GRF(1-29), written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-03-19 and is reviewed periodically as new material appears.
Naming in this area is inconsistent, and readers should treat product labels with care. In much of the literature and in vendor catalogs, the unqualified term refers to the albumin-binding version, while the version lacking the DAC group appears as modified GRF(1-29), mod GRF(1-29), or the same name with a without-DAC qualifier. Because one abbreviation has been applied to both materials, the only reliable way to identify a sample is to check the stated sequence and the presence of the linker.
CJC-1295 is the name used for a synthetic peptide modeled on growth hormone-releasing hormone, the hypothalamic signal that prompts the pituitary to release growth hormone. The compound was described by a Canadian drug discovery company in the mid-2000s as a long-acting research tool. Two closely related molecules share the name in practice: one carries a drug affinity complex, or DAC, group, and one does not. The distinction matters because the two behave differently in circulation.
The peptide backbone corresponds to GRF(1-29), the first 29 residues of native growth hormone-releasing hormone, which retains most of the receptor-activating activity of the full-length molecule. Four substitutions distinguish the analog from the natural sequence: D-alanine at position 2, glutamine at position 8, alanine at position 15, and leucine at position 27. These changes slow cleavage by dipeptidyl peptidase IV, the enzyme that degrades native hormone in plasma within minutes. The outcome is improved enzymatic stability combined with a still brief residence time when no additional modification is present.
Enzymatic protection is a separate mechanism from plasma protein binding. The four substitutions in the backbone reduce recognition by dipeptidyl peptidase IV, which normally cleaves the natural hormone within minutes. Without the reactive group, this resistance still yields only a short window of activity, generally reported in the range of tens of minutes. With it, reported half-lives in early human work extended to several days. The size of that gap is the main practical distinction between the two materials.
Both forms act at the pituitary receptor for growth hormone-releasing hormone and increase growth hormone output, which in turn raises insulin-like growth factor 1. A long-acting analog produces sustained rather than pulsatile stimulation, and the physiological consequences of that pattern are not fully settled. Published human data on the extended form remain limited, and much of what circulates in discussion traces to early company reports rather than independent replication. How sustained exposure affects normal feedback remains an open question.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic peptide | GHRH analog, not a steroid |
| Backbone length | 29 amino acids | Based on GRF(1-29) |
| Substitutions | Four positions | D-Ala2, Gln8, Ala15, Leu27 |
| Appearance | White to off-white powder | Typical lyophilized research material |
| Common synonyms | Modified GRF(1-29) | Usage varies between sources |
CJC-1295 is a synthetic peptide designed to mimic growth hormone-releasing hormone (GHRH), the endogenous signal that prompts the pituitary gland to release growth hormone. The compound is a modified fragment of the natural hormone, spanning the first twenty-nine amino acids of GHRH with several substitutions that slow enzymatic breakdown. Two variants circulate in research settings: one carrying a drug affinity complex (DAC) and one without it. The DAC-free form is frequently labelled Mod GRF(1-29) in catalogs and discussion forums.
The peptide binds GHRH receptors on somatotroph cells within the anterior pituitary, triggering a signalling cascade that increases growth hormone secretion. Its improved resistance to dipeptidyl peptidase IV degradation distinguishes it from the parent hormone. In the DAC-bearing version, a maleimide group reacts with a cysteine residue on serum albumin, forming a covalent bond that keeps the peptide in circulation far longer. That albumin attachment is the central design feature separating the two research variants.
CJC-1295 is a synthetic analogue of growth hormone-releasing hormone, built on the 29-amino-acid GHRH(1-29) fragment. Four substitutions distinguish it from the natural sequence: D-alanine at position 2, glutamine at position 8, alanine at position 15, and leucine at position 27. These changes reduce enzymatic cleavage and extend the peptide's persistence in circulation. The compound is discussed in two forms, one carrying a drug affinity complex and one without it.
The drug affinity complex is a maleimidopropionic acid group attached to a lysine side chain. It reacts with the free thiol of cysteine-34 on circulating albumin, forming a covalent bond. This conjugation keeps the peptide in the bloodstream and shields it from rapid renal filtration and proteolysis. Reported circulation half-lives for the albumin-bound form fall in the range of roughly six to nine days in early human studies.
Binding to GHRH receptors on pituitary somatotroph cells triggers cyclic AMP signaling and stimulates growth hormone synthesis and release. Because the peptide acts upstream of the pituitary, effects are mediated through endogenous growth hormone rather than direct receptor activation in peripheral tissues. Increases in insulin-like growth factor 1 are generally described as a downstream consequence. Most published human exposure data come from small early-stage studies, and the clinical significance of the pharmacokinetic profile remains incompletely characterized.
For diabatically enhanced classical events, at 24 hours prior to the onset of CAD, a prominent 250-mb jet extends from southwest to northeast across eastern North America. A general area of troughing is present at the 500- and 250-mb levels west of the jet. The parent high-pressure system is centered over the upper Midwest beneath the 250-mb jet entrance region, setting up conditions for CAD east of the Rocky Mountains. For dry onset classical events, the 250-mb jet is weaker and centered farther east relative to the diabatically enhanced classical events. The jet also does not extend as far southwest compared to diabatically enhanced classical CAD events. The center of the high-pressure system is farther east, so ridging extends southward into the south-central eastern United States. Although both types of classical events begin differently, their results are very similar.
=== Chimeric and humanized === To reduce murine antibody immunogenicity (attacks by the immune system against the antibody), murine molecules were engineered to remove immunogenic content and to increase immunologic efficiency. This was initially achieved by the production of chimeric (suffix -ximab) and humanized antibodies (suffix -zumab). Chimeric antibodies are composed of murine variable regions fused onto human constant regions. Taking human gene sequences from the kappa light chain and the IgG1 heavy chain results in antibodies that are approximately 65-75% human. This reduces immunogenicity, and thus increases serum half-life as the chimeric or humanized antibody is less likely to be recognized as foreign by the bodies immune system. Humanised antibodies are produced by grafting murine hypervariable regions on amino acid domains into human antibodies. This results in a molecule of approximately 95% human origin. Humanised antibodies bind antigen much more weakly than the parent murine monoclonal antibody, with reported decreases in affinity of up to several hundredfold. Increases in antibody-antigen binding strength have been achieved by introducing mutations into the complementarity determining regions (CDR), using techniques such as chain-shuffling, randomization of complementarity-determining regions and antibodies with mutations within the variable regions induced by error-prone PCR, E. coli mutator strains and site-specific mutagenesis.
A GnRH modulator, or GnRH receptor modulator, also known as an LHRH modulator or LHRH receptor modulator, is a type of medication which modulates the GnRH receptor, the biological target of the hypothalamic hormone gonadotropin-releasing hormone (GnRH; also known as luteinizing-releasing hormone, or LHRH). They include GnRH agonists and GnRH antagonists. These medications may be GnRH analogues like leuprorelin and cetrorelix – peptides that are structurally related to GnRH – or small-molecules like elagolix and relugolix, which are structurally distinct from and unrelated to GnRH analogues. GnRH modulators affect the secretion of the gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which in turn affects the gonads, influencing their function and hence fertility as well as the production of sex steroids, including that of estradiol and progesterone in women and of testosterone in men. As such, GnRH modulators can also be described as progonadotropic or antigonadotropic, depending on whether they act to increase or decrease gonadotropins. Shortly after the discovery of GnRH by Nobel laureates Guillemin and Schally, researchers tried to modify the GnRH decapeptide with the intent to create analogues that could activate or block the receptor. Subsequent to the development and introduction of GnRH analogues, non-peptide or small-molecule GnRH modulators were developed and introduced. All GnRH modulators are contraindicated in pregnancy (pregnancy category X).
=== Austrian Empire and Austria-Hungary === In 1814, by decisions of the Congress of Vienna, Tyrol was reunified and returned to Austria, becoming a crown land (Kronland) of the Austrian Empire. The formerly Salzburgian Zillertal, Brixental and Matrei were also permanently integrated into Tyrol. Administratively Vorarlberg was attached to the reconstituted Tyrol (formally as "the princely county of Tyrol with Vorarlberg" – die gefürstete Grafschaft Tirol mit Vorarlberg) as Kreis Bregenz until it became a crown land in its own right in the 1861 February Patent. Tyrol-proper (i.e. excluding Vorarlberg) was until 1849 divided into six Kreise: Oberinnthal (or Imst), Unterinnthal (Schwaz), Pusterthal (Bruneck), Etsch (Bozen), Trient and Rovereto. In 1849 this was reduced to three: Innsbruck, Brixen and Trient, which broadly corresponded with the modern North Tyrol, South + East Tyrol and Trentino respectively. These Kreise were briefly divided into modern-style political districts but were recentralised and divided into smaller "office districts" from 1853. Following the Austro-Hungarian Compromise of 1867 Tyrol was a Cisleithanian (Austrian) crown land within Austria-Hungary. The Kreise and office districts were abolished and political districts re-introduced in 1868.
Sources: en.wikipedia.org
== See also == Prokaryotic elongation factors EF-Ts (elongation factor thermo stable) EF-Tu (elongation factor thermo unstable) EF-P (elongation factor P) eEF2 (eukaryotic elongation factor 2) Protein translation GTPase
== Behaviour and ecology == Octopuses are mostly solitary though a few are known to live in groups and interact regularly, usually in the context of dominance and reproductive competition. This is likely the result of abundant food supplies combined with fewer den sites. The Larger Pacific striped octopus has been described as particularly social, living in groups of up to 40. Octopuses hide in dens, which are typically crevices in rocky or other hard structures, including man-made ones. Small species may use abandoned shells and bottles. They can navigate to a den without having to retrace their outward route. They are not migratory. Octopuses bring captured prey to the den to eat. Dens are often surrounded by a midden of dead and uneaten food items. These middens may attract scavengers such as fish, molluscs, and echinoderms. On rare occasions, octopuses hunt cooperatively with other species, with fish as their partners. They regulate the species composition of the hunting group – and the behaviour of their partners – by punching them.
Isoelectric focusing (IEF), also known as electrofocusing, is a technique for separating different charged molecules by differences in their isoelectric point (pI). It is a type of zone electrophoresis usually performed on proteins in a gel that takes advantage of the fact that overall charge on the molecule of interest, i.e. the net charge density, is a function of the pH of its surroundings.
Sources: en.wikipedia.org
No. It is a laboratory-made analog of growth hormone-releasing hormone. The natural hormone is a 44-residue peptide, while the analog is built on a shorter 29-residue fragment.
The original material included a linker that binds serum albumin. A later variant removed that linker to reduce the duration of action. Catalogs and papers did not consistently adopt separate names, so both remain widely labeled with the same term.
The amino acid sequence and the presence or absence of the linker group. Mass measured by spectrometry gives an independent check that separates the two forms.
A maleimide moiety reacts with the thiol of cysteine-34, forming a covalent bond. The reaction occurs in circulation without enzymatic catalysis.