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Background And Receptor Mechanism — Worked Examples

By Editorial Desk · published 2025-11-14 · last reviewed 2025-12-13 · Blog

The short version of CJC-1295 fits in a sentence. The long version — which is the one that helps — is below.

This page was last updated on 2025-12-13 and is reviewed periodically as new material appears.

Background and Receptor Mechanism

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.

Two principal forms appear in the literature and in research supply. One carries a drug affinity complex, a maleimide-based group that forms a covalent bond with circulating albumin. This linkage slows clearance and produces a long-lasting elevation of peptide levels. The other form lacks that group and is often labeled MOD GRF(1-29). It has a much shorter circulation time. Both variants retain the same core receptor-binding sequence. Reported half-lives differ substantially between the two.

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.

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.

Cjc-1295 at a glance

PropertyValueNotes
Molecular weight, DAC formAbout 3647 DaVaries with salt form
Molecular weight, non-DAC formAbout 3358 DaMOD GRF(1-29)
Solubility classWater solubleAlso dissolves in polar solvents
Reported half-life, DAC formAbout five to eight daysValues from human studies
Common synonymsCJC-1295; MOD GRF(1-29)Name depends on variant

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.

The attached maleimide group explains the unusual duration of the DAC version. After injection it reacts with the thiol of cysteine-34 on serum albumin, forming a stable covalent bond. The resulting conjugate is too large for rapid kidney filtration and is shielded from many peptidases. Reported half-lives for this form reach several days, whereas the version without the group is cleared in roughly half an hour. That gap is the main pharmacological difference between the two.

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Background and Molecular Features

The core sequence keeps the receptor-binding region of GHRH while replacing four positions that are vulnerable to dipeptidyl peptidase-4 and other proteases. Substitutions at positions 2, 8, 15, and 27 raise metabolic stability relative to the natural hormone. The N-terminal residues remain essential for activity, so changes there generally lower potency. Molecular weight sits near 3368 daltons for the tetrasubstituted analog without the linker, while the albumin-binding form is heavier because of the added maleimide group.

CJC-1295 is a synthetic peptide modeled on growth hormone-releasing hormone, the hypothalamic signal that prompts the pituitary to release growth hormone. Its sequence corresponds to the first twenty-nine residues of human GHRH, with four substitutions that slow enzymatic breakdown. Early descriptions placed the compound in research on growth hormone deficiency and related conditions, and later literature groups it with the long-acting GHRH analogs. The name appears in both laboratory and popular fitness writing, where it sometimes labels chemically different peptides.

Background from the literature

Levamisole is one of the most common cutting agents used to lace illicit cocaine, with studies showing that between 2009 and 2016, 50–70% of all cocaine specimens worldwide contained levamisole, reflecting similar high rates of contamination across North America and Europe. Before trafficking to the United States, the cocaine is frequently adulterated with levamisole. By October 2017, this figure had risen further, with the US Drug Enforcement Administration (DEA) reporting that 87% of seized and analyzed cocaine bricks in the United States contained levamisole, making it the most common adulterant in cocaine at that time. In the body, levamisole is converted into aminorex, a substance with amphetamine-like stimulant effects and a long duration of action. Levamisole-adulterated cocaine is associated with cocaine/levamisole-associated autoimmune syndrome (CLAAS) and cocaine- and levamisole-induced vasculitis (CLIV). Reagent testing kits can be used to detect the presence of cocaine and levamisole.

CRFB1 (IFNAR2-1) + CRFB5 (IFNAR1) binds group I CRFB2 (IFNAR2-2) + CRFB5 (IFNAR1) binds group II CRFB6 (IFNGR2) + 2× CRFB13 (IFNGR1-2) binds IFNg CRFB6 (IFNGR2) + 2× CRFB17 (IFNGR1-1) binds IFNgrel CRFB6 (IFNGR2) + CRFB13 (IFNGR1-2) + CRFB17 (IFNGR1-1) binds IFNg and possibly IFNgrel CRFB12 (IFNUR1) + CRFB4 (IL-10R2) binds type IV The split of type I into fish groups I, II and the many amniote Greek-letter groups happened independently, after the two groups of animals had diverged from each other. As a result, the only level of orthology between these grouping is that fish type I is as a whole orthologous to amniote type I. Much like in amniotes, the new copies of interferon have subfunctionalized in teleost fish.

Tegileridine, sold under the brand name Aisute, is a drug which acts as a μ-opioid receptor agonist. It is closely related to compounds such as oliceridine, TRV734, and SHR9352, and shares a similar profile as a biased agonist selective for activation of the G protein signalling pathway over β-arrestin2 recruitment. In January 2024, tegileridine was approved in China under the brand name Aisute for the treatment of moderate to severe pain after abdominal surgery.

== Sources in nature == Apigenin is found in many fruits and vegetables, but parsley, celery, celeriac, and chamomile tea are the most common sources. Apigenin is particularly abundant in the flowers of chamomile plants, constituting 68% of total flavonoids. Dried parsley can contain about 45 mg apigenin per gram. The apigenin content of fresh parsley is reportedly 215 mg per 100 grams, which is much higher than the next highest food source.

Sources: en.wikipedia.org

Reference notes

=== Myelosuppression === Proliferating cells, such as tumour cells, are more sensitive to alkylating agents, rendering these drugs useful for chemotherapy. However, alike drugs of this class, thiotepa is nonselective, which often results in its most important side effect: myelosuppression, the decreased activity of bone marrow. In turn, this can lead to leukopenia, thrombocytopenia, infection, and anemia. These side effects are often the most severe between 15 and 20 days following low dose treatment. Bone marrow has a high turn-over in the production of blood cells, which can be analogously inhibited by alkylating agents. This toxicity is dose-dependent and can be anticipated on. However, even a low dose can lead to life-threatening situations. Higher, and, therefore, more therapeutically effective, doses of thiotepa have successfully been applied by the autologous transplantation of bone marrow. In these high-dose therapies, the dose can be as much as a hundred times greater than that of conventional therapy. Despite the use of bone marrow transplantation, complications from the therapy can be fatal. Monoalkylation of DNA leads to mispairing of bases and, if not repaired, can reside in the DNA sequence. Mutated DNA that does not undergo cell death can find its way into daughter cells and potentially cause genetic disorders such as cancer. As a result of cell mutation in the bone marrow, chemotherapies with alkylating agents are known to cause acute myeloid leukaemia (AML) and myelodysplastic syndrome (MDS).

The number of hydrogen bonds formed by a molecule of liquid water fluctuates with time and temperature. From TIP4P liquid water simulations at 25 °C, it was estimated that each water molecule participates in an average of 3.59 hydrogen bonds. At 100 °C, this number decreases to 3.24 due to the increased molecular motion and decreased density, while at 0 °C, the average number of hydrogen bonds increases to 3.69. Another study found a much smaller number of hydrogen bonds: 2.357 at 25 °C. Defining and counting the hydrogen bonds is not straightforward however. Because water may form hydrogen bonds with solute proton donors and acceptors, it may competitively inhibit the formation of solute intermolecular or intramolecular hydrogen bonds. Consequently, hydrogen bonds between or within solute molecules dissolved in water are almost always unfavorable relative to hydrogen bonds between water and the donors and acceptors for hydrogen bonds on those solutes. Hydrogen bonds between water molecules have an average lifetime of 10−11 seconds, or 10 picoseconds.

Anhydrous hydrogen bromide is a poor solvent, only able to dissolve small molecular compounds such as nitrosyl chloride and phenol, or salts with very low lattice energies such as tetraalkylammonium halides.

== Adverse effects == Lercanidipine is generally well tolerated; no single adverse effect has been observed in more than 1% of patients treated with this drug. Typical side effects are similar to those of other drugs of this class and include headache, dizziness, tachycardia (fast heartbeat), palpitations, flush, and oedema. Hypersensitivity reactions occur in less than one patient in 10,000. Oedemas are significantly less common under lercanidipine when compared to first-generation dihydropyridines such as nifedipine. For other side effects, data are inconclusive: A study comparing lercanidipine to first-generation drugs found no difference in the frequency of headache and flush, but switching from amlodipine, felodipine or nitrendipine (all at least second generation) to lercanidipine significantly decreased side effects in another study.

==== Milestones of 1,500 RBI, 1,500 runs scored and 200 stolen bases (2004) ==== When he hit his sixth career grand slam against Milwaukee on April 9, 2004, Bagwell tied a club record. He recorded his 200th career stolen base on August 30 against Cincinnati to become the tenth player in MLB history to reach that plateau while hitting 400 home runs. On September 18, 2004, Bagwell collected his 1,500th career RBI with a single in the third inning against the Brewers. Two innings later, he homered for his 1,500th run scored, becoming just the 29th player in MLB history and the first Astro to reach both milestones. Bagwell finished with 27 home runs, stopping a streak of eight consecutive seasons with at least 30, but extending a streak of 12 with at least 20. The Astros faced the Braves in the playoffs for the fourth time in Bagwell's career in the 2004 NLDS. In Game 3, on October 7, he hit his first career postseason home run off Mike Hampton in the first inning in a 4–2 extra-inning loss. After three failed attempts to advance past the first round of the playoffs earlier in Bagwell's career, losing to Atlanta in 1997, 1999, and 2001, and seven overall in 43 years of franchise history, the Astros defeated the Braves for their first-ever playoff series win. The quartet dubbed the "Killer B's," this time including Carlos Beltrán and Lance Berkman, ignited the Astros' offense, batting .395 (34-for-86) with eight home runs, 21 RBI and 24 runs scored. The Astros scored an NLDS-record 36 runs in all and Bagwell batted .318 with two home runs and five RBI.

Sources: en.wikipedia.org

Reference notes

=== Cluster headaches === Preventive therapy with verapamil is believed to work because it has an effect on the circadian rhythm and on CGRPs, as CGRP-release is controlled by voltage-gated calcium channels.

== References == This article incorporates material from the Citizendium article "Drugs banned from the Olympics", which is licensed under the Creative Commons Attribution-ShareAlike 3.0 Unported License but not under the GFDL.

Dom Pothier died at the old priory of Conques, Belgium in 1923; the Bishop of Luxembourg and six prelates attended his funeral at Clervaux abbey, Luxembourg (his remains later were transferred to Saint-Wandrille in 1962). The exiled community of St Wandrille's Abbey, under Dom Pothier as Abbot, founded in 1912 a new priory in Canada, Saint Benedict Abbey, Quebec, which later became independent within the Solesmes Congregation.

=== Brain growth === Neuroanatomical studies and the association between autism and teratogens strongly suggest that autism affects brain development soon after conception. This anomaly appears to start a cascade of pathological events in the brain that are significantly influenced by environmental factors. Just after birth, the brains of children with autism tend to grow faster than usual, followed by normal or relatively slower growth in childhood. It is unknown whether early brain overgrowth occurs in all children with autism. It appears to be most prominent in the frontal and temporal lobes, which are associated with higher cognitive specializations such as social cognition, and language development. Hypotheses for the cellular and molecular bases of pathological early overgrowth include an excess of neurons that causes local overconnectivity in key brain regions, and disturbed neuronal migration during early gestation.

=== Airglow of the Earth === The Earth's night sky is illuminated by diffuse light, called airglow, that is produced by radiative transitions of atoms and molecules. Among the most intense such features observed in the Earth's night sky is a group of infrared transitions at wavelengths between 700 nanometers and 900 nanometers. In 1950, Aden Meinel showed that these were transitions of the hydroxyl molecule, OH.

Sources: en.wikipedia.org

Frequently asked questions

What is CJC-1295?

It is a synthetic peptide modeled on growth hormone-releasing hormone. The molecule is used in research on pituitary growth hormone secretion. It differs from the natural hormone through several stabilizing substitutions.

How do the DAC and non-DAC forms differ?

The DAC form carries a maleimide group that binds albumin and extends circulation time. The non-DAC form lacks this group and clears much faster. Both share the same receptor-binding core.

What receptor does it act on?

It targets the growth hormone-releasing hormone receptor on pituitary somatotroph cells. Activation raises cyclic AMP and promotes growth hormone release. Normal feedback pathways remain part of the response.

Does this compound occur naturally in the body?

No. It is a laboratory-synthesized analog built on a fragment of the natural hormone. The natural peptide is shorter-lived and lacks the stabilizing substitutions found in the synthetic version.

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