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Structure And Receptor Pharmacology — Deep Dive

By Editorial Desk · published 2026-03-10 · last reviewed 2026-04-25 · News

If you have been reading about GRF(1-29) and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.

Last reviewed on 2026-04-25. Where a claim depends on a specific study, the study is described rather than over-claimed.

Structure And Receptor Pharmacology

Receptor level activity follows the canonical GHRH pathway. The peptide binds the GHRH receptor, a class B G protein coupled receptor on somatotroph cells of the anterior pituitary. Binding raises intracellular cyclic AMP, which promotes calcium entry and the release of growth hormone into the bloodstream. Because the molecule acts at the same receptor as the endogenous hormone, its effect is superimposed on the natural pulsatile rhythm rather than replacing it. Whether sustained receptor occupation leads to desensitization is not fully settled.

CJC-1295 belongs to a class of synthetic peptides modeled on growth hormone releasing hormone, a forty-four amino acid signal produced by the hypothalamus. The compound is built from the first twenty-nine residues of the natural sequence, with four substitutions introduced at positions 2, 8, 15 and 27. These changes were designed to slow enzymatic breakdown while preserving receptor activation. The result is a peptide that is shorter than native GHRH and considerably more resistant to ordinary clearance pathways in circulation.

Analytical Measurement And Stability

Lyophilized material is generally stable for extended periods when held at minus twenty degrees Celsius or below and protected from moisture and light. In solution the peptide is more labile; bond hydrolysis, aggregation and oxidation of susceptible residues all proceed faster at ambient temperature. Repeated freeze and thaw cycles should be avoided because they promote clumping and loss of soluble material. The conjugated variant adds a further consideration, since the maleimide group can hydrolyze in aqueous buffer and lose its ability to react with albumin.

Laboratory handling centers on minimizing exposure to water, heat and oxygen before use. Working solutions are typically prepared in sterile water or a mild buffer, and any residual particulate matter is removed by filtration. When the powder dissolves slowly, a small proportion of acetonitrile or dilute acetic acid is sometimes added as a co-solvent. Containers are kept sealed and desiccated between uses. Records of lot number, reconstitution date and storage conditions support later comparison of results across experiments.

Cjc-1295 at a glance

PropertyValueNotes
Peptide classSynthetic GHRH analogueBuilt on a 29 residue sequence
Primary targetGHRH receptor (GHRHR)Class B G protein coupled receptor
Unconjugated half lifeMinutesLimited by protease degradation
Key modificationFour residue substitutionsPositions 2, 8, 15 and 27
Common synonymModified GRF(1-29)Usually denotes the form without DAC

Background and Receptor Mechanism

At the pituitary, the peptide binds the growth hormone-releasing hormone receptor on somatotroph cells. Receptor activation raises intracellular cyclic AMP and triggers release of stored growth hormone. Somatostatin and other hypothalamic signals modulate this response. Negative feedback from insulin-like growth factor 1 also influences output. The same regulatory architecture operates with the native hormone. Whether the synthetic analog alters feedback dynamics over repeated exposure remains an open question. Most published receptor work uses cell models rather than intact human systems.

CJC-1295 is a synthetic peptide belonging to the growth hormone-releasing hormone analog family. It comprises twenty-nine amino acid residues derived from the N-terminal region of natural GHRH. The molecule incorporates several non-natural substitutions that increase resistance to enzymatic degradation. These modifications extend its activity compared with the native hormone fragment. Researchers use it to study pituitary growth hormone secretion in laboratory and clinical settings. This compound is distinct from native GHRH in its stability profile.

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Handling Storage and Quality Control

Reverse-phase high-performance liquid chromatography is the standard tool for purity assessment. The technique separates the target peptide from truncated or modified byproducts. Mass spectrometry confirms molecular weight and supports sequence verification. Electrospray ionization and matrix-assisted laser desorption are both used. Amino acid analysis provides an independent check on composition. Purity values are commonly reported as area percentage from the chromatogram. Residual trifluoroacetate and water content are also measured in many quality programs.

Batch-to-batch consistency depends on solid-phase peptide synthesis and subsequent purification. Coupling efficiency, resin choice, and cleavage conditions all affect the final profile. Counter-ion content and moisture can shift the apparent mass of a batch. Documentation typically includes a certificate of analysis with chromatograms and spectra. Independent verification by a second laboratory is sometimes requested. Whether a given certificate reflects the actual vial contents depends on chain of custody. Analytical methods themselves carry uncertainty that should be stated alongside results.

Molecular Background and Naming

CJC-1295 is a synthetic peptide designed as a long-acting analogue of growth hormone-releasing hormone (GHRH). Its structure derives from the first 29 amino acids of native GHRH, a fragment often called GRF(1-29). Four substitutions were introduced to slow enzymatic breakdown and extend activity relative to the natural sequence. The compound was developed by ConjuChem as part of a broader effort to improve the pharmacokinetic profile of peptide hormones. It is studied in laboratory and clinical research settings rather than appearing as a naturally occurring substance.

Two related forms circulate in technical discussion under the same family name. The original version carries a drug affinity complex (DAC) that binds covalently to serum albumin after administration, and this linkage substantially extends circulation time. A second form, frequently written as modified GRF(1-29) or CJC-1295 without DAC, lacks that linker and clears much faster. The naming is a frequent source of confusion because the shorthand CJC-1295 can refer to either form depending on the source. Reports sometimes fail to specify which variant was studied.

Background and Naming Conventions

The dividing feature between the two forms is a maleimide-based drug affinity complex, abbreviated DAC. In the DAC-bearing version, a linker attaches the peptide to serum albumin after administration, and that association slows removal from plasma. The version lacking DAC appears in catalogs as MOD GRF(1-29) or tetrasubstituted GRF(1-29). Because informal writing treats both as one item, comparisons drawn from such sources routinely blend measurements taken from two molecules with substantially different behavior.

Four amino acid substitutions separate the modified backbone from the parent GRF(1-29) sequence. These changes reduce recognition by dipeptidyl peptidase IV and related proteases, extending the interval before degradation. Development work in this area sought longer-acting GHRH analogs for endocrine investigation. Published descriptions treat the substitution set as a defining property of the core sequence, while the albumin-binding linker is described separately as an optional addition to that same backbone.

CJC-1295 is a synthetic peptide analog of growth hormone-releasing hormone, constructed on the 29-amino-acid fragment designated GRF(1-29). The name began as an internal development code during the 1990s and later spread through research supply catalogs and discussion forums. The molecule does not occur in nature; its sequence is engineered rather than isolated from tissue. Two related compounds are sold under this single label, and they differ by one appended chemical group that strongly influences how long the peptide remains in circulation.

Reference notes

AMP + H2O + H+ → IMP + NH3 The second stage is the formation of adenylosuccinate from IMP and the amino acid aspartate, which is coupled to the energetically favourable hydrolysis of GTP, and catalysed by the enzyme adenylosuccinate synthetase:

== Usage == Silverside beef is a lean cut, and thus is often cooked via braising or other indirect heating methods in a pot roast recipe. It may also be thinly sliced for minute steak or beef olives, or butterflied to enhance tenderness. In South Africa, Australia, Ireland and New Zealand, silverside is the cut of choice for corning or brining, so much so that the name "silverside" is often used to refer to corned beef (also called salt beef) rather than any other form of the cut. In South Africa this cut is often used to make biltong (a form of dried, cured meat).

=== Research === A major thread of Bumpus' research is determining how antiviral drugs used to treat HIV-1 are metabolized and how genetic variations in drug-processing enzymes may impact these drugs' efficacy. One antiviral commonly used to treat and prevent HIV is tenofovir (Viread). Tenofovir is a nucleotide analog reverse transcriptase inhibitor that prevents the HIV virus from replicating. Tenofovir is given in an inactive form – it has to be phosphorylated twice to become active, and this phosphorylation is carried out in two steps by separate kinases. Bumpus and her team identified which kinases do this and found that the enzymes responsible varied by cell type, so administration route (e.g. orally or topically) could affect how effectively the drug is processed. They also sequenced the genes of these kinases from different patients and found that some people have genetic variants in the kinases that may affect how effectively the drug is processed. Tenofovir can be given prophylactically, and Bumpus collaborated with researchers from around the world in a study of the use of tenofovir for HIV pre-exposure prophylaxis (PrEP) to prevent HIV infection in heterosexual men and women. Bumpus has also researched nonnucleoside reverse transcriptase inhibitors. Her lab was the first to publish the P450-catalyzed phase 1 and phase 2 metabolic pathways of two nonnucleoside reverse transcriptase inhibitors, rilpivirine and etravirine and was first to characterize the metabolism of the nonnucleoside reverse transcriptase inhibitor dapivirine.

=== Venture capital === Verdine has worked in the venture capital industry as a Venture Partner with Apple Tree Partners, Third Rock Ventures, and WuXi Healthcare Ventures, and as a Special Advisor to Texas Pacific Group.

Sources: en.wikipedia.org

Notes from published material

== Sources == Barnard, Catherine (2013). The substantive law of the EU : the four freedoms (4th ed.). Oxford University Press. ISBN 978-0-19-967076-5. (later editions are available) Barnard, Catherine & Steve Peers, eds. European Union law, 4th edn. Oxford: Oxford University Press, 2023. Bogusz, Barbara; Berry, Elspeth; Strecker, Sophie (2025). Complete EU Law: Text, Cases, and Materials (6th ed.). Oxford: Oxford University Press. ISBN 9780198930327. Butler, Graham; Wessel, Ramses A (2022). EU External Relations Law: The Cases in Context. Oxford: Hart Publishing/Bloomsbury. ISBN 978-1-5099-3969-5. Craig, Paul; de Búrca, Gráinne (2011). The evolution of EU Law (2nd ed.). Oxford University Press. ISBN 978-0-19-959296-8. (later editions are available) Craig, Paul; de Búrca, Gráinne (2015). The evolution of EU Law (2nd ed.). Oxford University Press. ISBN 978-0-19-882118-2. Craig, Paul; de Búrca, Gráinne (2024). EU Law: Text, Cases, and Materials (8th ed.). Oxford University Press. ISBN 9780198915553. Dickson, Julie & Paulos Eleutheriadēs, eds. Philosophical foundations of European Union law. Oxford: Oxford University Press, 2012. Hartley, Trevor (2014). The foundations of European Union law : an introduction to the constitutional and administrative law of European Union. Oxford University Press. ISBN 978-0-19-873467-3. Horspool, Margot; Humphreys, Matthew; Wells-Greco, Michael. European Union Law (11th ed.). Oxford: Oxford University Press. ISBN 9780192643452. McGaughey, Ewan (2022). Principles of Enterprise Law: the Economic Constitution and Human Rights.

"Brazil does not grant unilateral exemptions of visitor visas, without reciprocity, to other countries. [...] In attention to the interests of Brazilian citizens, the Brazilian government will be ready to continue negotiating, with the four aforementioned countries, visa waiver agreements on reciprocal bases." — Ministry of Foreign Affairs (Itamaraty). The return of visa charges was received with criticism by some entities linked to the tourism and hospitality sector. For Feliciano Sá Guimarães, director of the Brazilian Center for International Relations, the measure is an obstacle to the development of national tourism and "a vain retrograde nationalist defense". Although the National Confederation of Tourism (Cntur) "did not view it favorably", Wilson Luis Pinto, executive president of the entity, stated that he believed the government took a calculated measure and that the country would not cease to be an option for foreign travelers. "Whoever decided they want to come here will come." Luis Pinto also expressed support for the proposal: "I, as a Brazilian, do not think it is fair to spend months in line and pay a fee to obtain a visa, while an American can buy a ticket and come to Brazil". The government assessed that the resumption of visas would have a low impact on tourism and, according to the Polícia Federal, although in 2019 there were some peaks in the entry of people from North America into Brazil after the visa exemption, this number did not show much increase compared to the period before the measure.

==== Other caves of the third period ==== The Center Cave (Cave 186), the Third to Last Cave (Cave 184) and the Third Cave from the Front (Cave 187) are also considered as representatives of this third period.

Previously, many studies used Mass Spectrometry (MS) in different fragmentation modes to detect AMPylated peptides. In responses to the distinctive fragmentation techniques, AMPylated protein sequences disintegrated at different parts of AMP. While electron transfer dissociation (ETD) creates minimum fragments and less complicated spectra, collision-induced dissociation (CID) and high-energy collision (HCD) fragmentation generate characteristic ions suitable for AMPylated proteins identification by generating multiple AMP fragments. Due to AMP's stability, peptide fragmentation spectra is easy to read manually or with search engines. Inhibitors of protein AMPylation with inhibitory constant (Ki) ranging from 6 - 50 μM and at least 30-fold selectivity versus HypE have been discovered.

Since 1991, the year the Gulf War ended, veterans and their families voiced concern about subsequent health problems. In 1999, an assessment of the first 1,000 veterans involved in the Ministry of Defence's Gulf War medical assessment programme found "no evidence" of a single illness, physical or mental, that would explain the pattern of symptoms observed in the group. In 1999, MEDACT petitioned for the WHO to conduct an investigation into illnesses in veterans and Iraqi civilians. A major 2006 review of peer-reviewed literature by a US Institute of Medicine (IOM) committee concluded that, "[b]ecause the symptoms vary greatly among individuals", they do not point to a syndrome unique to Gulf War veterans, though their report conceded that the lack of objective pre-deployment health data meant definitive conclusions were effectively impossible. Simon Wessely praised the IOM's review, and noted that, despite its central conclusion that no novel syndrome existed, its other findings made it "equally clear that service in the Gulf war did adversely affect health in some personnel". Aside from the lack of baseline data to guide analysis of the veterans' postwar health, because no detailed health screening was carried out when the veterans entered service, another major stumbling block with some studies, like the thousand-veteran one, is that the subjects are self-selected, rather than a random sample, making general conclusions impossible.

Sources: en.wikipedia.org

Further detail

== HFE mutations and iron overload in other animals == The black rhinoceros (Diceros bicornis) can develop iron overload. To determine whether the HFE gene of black rhinoceroses has undergone mutation as an adaptive mechanism to improve iron absorption from iron-poor diets, Beutler et al. sequenced the entire HFE coding region of four species of rhinoceros (two browsing and two grazing species). Although HFE was well conserved across the species, numerous nucleotide differences were found between rhinoceros and human or mouse, some of which changed deduced amino acids. Only one allele, p.S88T in the black rhinoceros, was a candidate that might adversely affect HFE function. p.S88T occurs in a highly conserved region involved in the interaction of HFE and TfR1.

The addition of S. boulardii to standard triple therapy for the eradication of Helicobacter pylori infection has been associated with a modest but statistically significant increase in eradication rates in a meta-analysis. The same analysis also reported a significant reduction in common adverse effects of eradication therapy, including diarrhea and nausea.

White fat cells contain a single large lipid droplet surrounded by a layer of cytoplasm, and are known as unilocular. The nucleus is flattened and pushed to the periphery. A typical fat cell is 0.1 mm in diameter with some being twice that size, and others half that size. However, these numerical estimates of fat cell size depend largely on the measurement method and the location of the adipose tissue. The fat stored is in a semi-liquid state, and is composed primarily of triglycerides, and cholesteryl ester. White fat cells secrete many proteins acting as adipokines such as resistin, adiponectin, leptin and apelin. An average human adult has 30 billion fat cells with a weight of 30 lbs or 13.5 kg. If a child or adolescent gains sufficient excess weight, fat cells may increase in absolute number until age twenty-four. If an adult (who never was obese as a child or adolescent) gains excess weight, fat cells generally increase in size, not number, though there is some inconclusive evidence suggesting that the number of fat cells might also increase if the existing fat cells become large enough (as in particularly severe levels of obesity). The number of fat cells is difficult to decrease through dietary intervention, though some evidence suggests that the number of fat cells can decrease if weight loss is maintained for a sufficiently long period of time (>1 year; though it is extremely difficult for people with larger and more numerous fat cells to maintain weight loss for that long a time).

== See also == List of abbreviations used in medical prescriptions List of medical roots, suffixes and prefixes Medical dictionary Medical slang Abbreviation#Style conventions in English Acronym and initialism#Orthographic styling

Sources: en.wikipedia.org

Frequently asked questions

Is CJC-1295 the same as modified GRF(1-29)?

The names are often used interchangeably in casual writing, but they are not strictly identical. Modified GRF(1-29) refers to the unconjugated analogue carrying only the four substitutions. The version sold as CJC-1295 with DAC includes the albumin binding linker and clears much more slowly.

What does the acronym DAC refer to?

DAC stands for drug affinity complex, a term describing the maleimidopropionic acid linker. This group forms a covalent bond with the cysteine residue on serum albumin after administration. The resulting adduct is what extends the circulating half life from minutes to days.

Does this peptide occur naturally in the body?

No. It is entirely synthetic and does not correspond to any known endogenous peptide. The design starts from human growth hormone releasing hormone and introduces deliberate substitutions. Any biological effect comes from mimicking the natural hormone at its receptor.

How are the two variants distinguished in a laboratory?

The mass difference from the linker is large enough for routine detection by mass spectrometry. The unconjugated form gives a single sharp signal at its expected weight. Material that has already reacted with albumin shows a much higher mass and a broadened chromatographic peak.

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