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Structure And Receptor Pharmacology — Beginner to Advanced

By Editorial Desk · published 2025-12-10 · last reviewed 2026-01-29 · Data

If you have been reading about CJC-1295 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.

Updated 2026-01-29. Numbers and descriptions here follow the published literature rather than marketing material.

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.

Receptor Action and Pharmacokinetics

Downstream of growth hormone, the liver and other tissues increase production of insulin-like growth factor 1, a mediator of many growth-promoting effects. Studies have documented elevated levels of both hormones after dosing, and the rise from the long-acting form persists longer than that produced by shorter-acting analogues. What remains unclear is whether sustained elevation of these markers translates into meaningful clinical benefit, and whether prolonged exposure carries risks that short trials could not detect.

CJC-1295 acts at the growth hormone-releasing hormone receptor, a G-protein-coupled receptor found on somatotroph cells in the anterior pituitary. Binding triggers a rise in cyclic AMP and calcium entry, which promotes release of stored growth hormone. Because the peptide mimics the body's own releasing hormone, it amplifies existing secretory pulses rather than driving continuous output. The size of the response therefore depends partly on the subject's own hormonal rhythm and feedback state.

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

CJC-1295 Structure And Mechanism

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.

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.

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Molecular Background and Naming

The peptide backbone includes a D-alanine at position two, which resists cleavage by dipeptidyl peptidase IV, and several other substitutions that reduce degradation. Its molecular weight is roughly 3.4 kDa without the linker and about 3.6 kDa with it. The molecule is water soluble and is normally supplied as a lyophilized powder. Precise sequence and mass values depend on which variant is described, so technical documents usually state the exact form being referenced.

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.

Mechanism and Pharmacokinetics

Studies in this area generally track growth hormone pulses, insulin-like growth factor 1 concentrations, and occasionally body composition endpoints. Most published human data come from early, small trials, and questions about long-term effects remain open. Whether repeated exposure alters pituitary responsiveness over time is not settled. Analytical work relies on immunoassays for the hormones and on mass spectrometry for the peptide itself, because the two measurements answer different questions.

Binding of the peptide to the growth hormone-releasing hormone receptor on pituitary somatotrophs triggers a G protein coupled cascade that raises cyclic AMP and opens calcium channels. The result is greater secretion of growth hormone into the bloodstream. Because the peptide acts at the same receptor as the natural hypothalamic hormone, its effect is amplified pulse size rather than an entirely separate release pathway. Receptor binding alone does not determine the response, since somatostatin tone and other inputs modulate the final output.

Further detail

== Nonionic kosmotropes == Nonionic kosmotropes have no net charge but are very soluble and become very hydrated. Carbohydrates such as trehalose and glucose, as well as proline and tert-butanol, are kosmotropes.

For dinosterol derivatives, analysis is typically carried out by capillary gas chromatography and capillary gas chromatography-mass spectrometry. The mass spectrum of dinosterol as the TMS-ether shows characteristic ions at m/z 500 (M+), 429, 388, 359, 339 and 271. The base peak at m/z 69 is diagnostic for the A:2-unsaturated 23,24-dimethyl sidechain. Other purification techniques for dinosterol include various combinations of thin layer (TLC) and column chromatography with a variety of phases, AgNO3 impregnated Silica gel chromatography, normal phase-high performance liquid chromatography (NP-HPLC), and reversed phase-high performance liquid chromatography (RP-HPL).An alternative method has been proposed for purifying dinosterol from complex mixtures of sedimentary lipids for the purpose of hydrogen isotope analysis via gas chromatography-isotope ratio mass spectrometry (GC-IRMS). Reversed phase-high performance liquid chromatography (RP-HPLC) is used to separate dinosterol from structurally similar 4α-methyl sterols that co-elute on GC analysis, which allows for baseline resolution of dinosterol. For samples that contain a variety of 4a-methyl sterols, RP-HPLC purification can be preceded by NP-HPLC purification.

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=== Bacterial pathogenicity === Bacteria proteins, also known as effectors, have been shown to use AMPylation. Effectors such as VopS, IbpA, and DrrA, have been shown to AMPylate host GTPases and cause actin cytoskeleton changes. GTPases are common targets of AMPylators. Rho, Rab, and Arf GTPase families are involved in actin cytoskeleton dynamics and vesicular trafficking. They also play roles in cellular control mechanisms such as phagocytosis in the host cell. The pathogen enhances or prevents its internalization by either inducing or inhibiting host cell phagocytosis. Vibrio parahaemolyticus is a Gram-negative bacterium that causes food poisoning as a result of raw or undercooked seafood consumption in humans. VopS, a type III effector found in Vibrio parahaemolyticus, contains a Fic domain that has a conserved HPFx(D/E)GN(G/K)R motif that contains a histidine residue essential for AMPylation. VopS blocks actin assembly by modifying threonine residue in the switch 1 region of Rho GTPases. The transfer of an AMP moiety using ATP to the threonine residue results in steric hindrance, and thus prevents Rho GTPases from interacting with downstream effectors. VopS also adenylates RhoA and cell division cycle 42 (CDC42), leading to a disaggregation of the actin filament network. As a result, the host cell's actin cytoskeleton control is disabled, leading to cell rounding. IbpA is secreted into eukaryotic cells from H. somni, a Gram-negative bacterium in cattle that causes respiratory epithelium infection. This effector contains two Fic domains at the C-terminal region.

The decrease in BMD during elagolix therapy may not be fully reversible with discontinuation, as only partial recovery was observed 12 months after discontinuation of therapy. The cause of the decrease in BMD with elagolix is estrogen deficiency, and is analogous to that associated with postmenopause. The consequences of the effects of elagolix on BMD are unknown, but may be an increase in the risk of bone loss and fractures. This is why the duration of use of elagolix should be limited. In women with risk factors for bone loss and osteoporosis, such as a history of low-trauma fracture, assessment of BMD may be considered. Elagolix should not be used in premenopausal women with known osteoporosis. Supplementation with calcium and/or vitamin D during treatment with elagolix has not been studied, but may be beneficial for helping to maintain bone health. Elagolix decreases the amount, intensity, and duration of menstrual bleeding. Amenorrhea, the cessation of menstruation, was observed in 4 to 17% of women with 150 mg once per day and in 7 to 57% of women with 200 mg twice per day, compared to less than 1% of women given placebo. The decreased menstrual bleeding caused by elagolix may impede the ability to recognize pregnancy in a timely manner. Based on its mechanism of action, elagolix may increase the risk of miscarriage in early pregnancy, and so should be discontinued if pregnancy occurs. If pregnancy is suspected, pregnancy testing can be performed.

Sources: en.wikipedia.org

Background from the literature

In particular, the Osedax worm lacks specific gene families involved in bone lipid and carbohydrate metabolism. This function is complemented by the Oceanospirillales symbionts, which utilize the glyoxylate cycle to catabolize nutrients from whale bones and convert fatty acids into carbohydrates. The Osedax are then able to take up and store the end products as glycogen. Bacteriocytes are present in the Osedax lower trunk subepidermal connective tissue, and there are additional genes in the bacteriocytes that encode amino acids and glucose and aid in digestion and absorption of proteins into the roots.

== Food safety == In its annual reports, Chipotle has acknowledged that it "may be at a higher risk for food-borne illness outbreaks than some competitors due to our use of fresh produce and meats rather than frozen, and our reliance on employees cooking with traditional methods rather than automation". Following the 2015 outbreaks, some food safety experts and media commentators argued that the variety of pathogens involved pointed to systemic problems with the company's food handling practices. On December 10, 2015, CEO Steve Ells released a statement apologizing for the outbreaks and promised changes to minimize future risks. Chipotle's official sustainability reports details their environmental goals and sourcing practices.

Many factors must be considered with intracerebroventricular injection to maintain safety. Some of these factors include osmolarity, pH, volume, and the presence of preservatives in the drug solution. Also, intracranial pressure, cerebrospinal fluid bulk flow rate, and buffering capacity have an impact on the distribution and safety of the injected drug. A major concern of ICV injection is neurovascular injury and intracranial hemorrhage. The risk of these conditions increases with each additional injection or "tap". For this reason, if repeated taps are needed, a catheter-based device can be implanted. These devices are connected to a subcutaneous reservoir, the most common being the Ommaya reservoir. This can be accessed multiple times, with a sterile puncture through the scalp into the reservoir. There is also an associated risk of infection with this method, but it is less likely than other methods of accessing the intraventricular space. Other rare complications with this method include leukoencephalopathy, white matter necrosis, and intracerebral hemorrhage. Other complications can occur with this procedure, and they can be divided into infectious and noninfectious categories. Of the noninfectious complications, the most frequently reported were CSF leaks, hemorrhage, catheter malposition, catheter obstruction, and device malfunction. In one study, the most likely cause for device removals was due to infectious complications (73.75 percent). Of the infections, the most common cause was skin flora.

While there's not much of a relationship between this hormone and physical plant behavior, there are behavioral changes that go on inside the plant in response to it. Cytokinin defense effects can include the establishment and growth of microbes (delay leaf senescence), reconfiguration of secondary metabolism or even induce the production of new organs such as galls or nodules. These organs and their corresponding processes are all used to protect the plants against biotic/abiotic factors.

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 does CJC-1295 raise growth hormone levels?

It binds the growth hormone-releasing hormone receptor on pituitary somatotroph cells. Receptor activation raises cyclic AMP and promotes release of stored growth hormone granules. Because the peptide persists longer than natural releasing hormone, stimulation is prolonged rather than brief.

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