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Structure And Receptor Pharmacology — Hands-On Walkthrough

By Editorial Desk · published 2026-02-26 · last reviewed 2026-04-17 · Wiki

GHRH analog comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.

Updated 2026-04-17. 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.

Analytical Characterization and Storage

Verification matters because research peptides vary widely in quality. A certificate of analysis is only as reliable as the method behind it, and a single chromatographic trace reveals little about counter-ions, residual solvents, or water content. Independent laboratories commonly pair mass confirmation with chromatographic purity and, where relevant, quantify water along with acetate or trifluoroacetate content. Reported purity figures are not standardized across suppliers, so a stated value such as ninety-eight percent is not directly comparable unless the analytical method, column, and detection wavelength accompany it.

Characterization of this peptide relies on a small set of routine techniques. Reversed-phase high-performance liquid chromatography separates the target from truncated or oxidized by-products and yields a purity estimate when paired with ultraviolet detection near 214 nanometers. Mass spectrometry, either electrospray coupled to liquid chromatography or matrix-assisted laser desorption, confirms that the observed mass matches the value calculated for the expected sequence. Amino acid analysis, and enzymatic digestion followed by fragment mapping, are used when the sequence itself rather than the mass requires verification.

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 Molecular Design

CJC-1295 belongs to a family of synthetic peptides modeled on growth hormone-releasing hormone, the hypothalamic signal that prompts the pituitary to release growth hormone. The compound is built from the first twenty-nine amino acids of the natural human sequence, a fragment that retains full receptor binding capacity. Native growth hormone-releasing hormone is degraded quickly in circulation, so the fragment alone has limited practical value. Early work therefore focused on chemical modifications that preserve receptor binding while slowing enzymatic breakdown. The result is a molecule described in the literature as a long-acting analog of the natural hormone.

Two forms circulate under the CJC-1295 name, and they differ by a single appended group. The version without a drug affinity complex carries four substitutions along the peptide chain, including a D-alanine near the amino terminus and replacements at three other positions. These changes block the enzyme dipeptidyl peptidase IV and remove a methionine residue that is prone to oxidation. The modified fragment is frequently labeled MOD GRF 1-29. Naming conventions are inconsistent across informal sources, which is a common source of confusion.

The second form adds a maleimide-bearing linker to the lysine at the carboxyl end. This group reacts with cysteine-34 on circulating serum albumin, forming a covalent bond that keeps the peptide in the bloodstream for far longer. ConjuChem developed the molecule as a way to extend the action of a peptide without frequent administration. The albumin attachment is the defining structural feature of the drug affinity complex version. Whether continuous exposure produces effects distinct from shorter pulses remains an unresolved research question.

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Compound Identity and Development History

Two forms circulate in research settings and are frequently confused. One carries the drug affinity complex and is often written as CJC-1295 with DAC; the other lacks that group and is usually called modified GRF(1-29). The two share the same core sequence but differ sharply in how long they persist in blood. Products labelled only as CJC-1295 normally refer to the version carrying the complex. Documentation that omits the distinction leaves the intended molecule ambiguous.

CJC-1295 is a synthetic peptide built as a long-acting analogue of growth hormone-releasing hormone. Its backbone matches the first twenty-nine residues of the natural human hormone, with four amino acid substitutions added to slow enzymatic breakdown. A reactive maleimide group, commonly termed the drug affinity complex, allows the peptide to attach to circulating albumin after administration. That albumin attachment keeps the molecule in the bloodstream for an extended period instead of being cleared within minutes.

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.

Background and Naming Conventions

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

The emperors Leo III (r. 717–741) and Constantine V (r. 741–775) were effective leaders, both in government and warfare. They withstood continued Arab attacks, as well as civil war and natural disasters. Constantine's success reestablished the state as a major regional power. Leo's reign produced the Ekloge ton nomon, a code of law that evolved that of Justinian I. He also continued to reform the theme system in order to lead offensive campaigns against the Muslims, culminating in a notable victory in 740. Constantine overcame an early civil war against his brother-in-law Artabasdos, created stability against the new Abbasid Caliphate, campaigned successfully against the Bulgars, and continued to make administrative and military reforms. Both emperors supported iconoclast policies opposing the veneration of religious images, which had them later vilified by biased authors, creating issues that continue to impact modern scholarship; Constantine's reign also saw the loss of Ravenna to the Lombards, and the beginning of a split from the Roman papacy. In 780, Empress Irene assumed power as regent for her son Constantine VI. Although she was a capable administrator who restored the veneration of icons, the empire was destabilised by her conflict with her son. The Bulgars and Abbasids inflicted numerous defeats on the Byzantine armies, and the papacy crowned Charlemagne as Roman emperor in 800. In 802, the unpopular Irene was overthrown by Nikephoros I; he reformed the empire's administration but died in battle against the Bulgars in 811.

=== Bioorthogonality === The azide can act as a soft electrophile that prefers soft nucleophiles such as phosphines. This is in contrast to most biological nucleophiles which are typically hard nucleophiles. The reaction proceeds selectively under water-tolerant conditions to produce a stable product. Phosphines are completely absent from living systems and do not reduce disulfide bonds despite mild reduction potential. Azides had been shown to be biocompatible in FDA-approved drugs such as azidothymidine and through other uses as cross linkers. Additionally, their small size allows them to be easily incorporated into biomolecules through cellular metabolic pathways.

=== 19th century: Early history === Dairy Farm Company Ltd was set up in 1886 by Sir Patrick Manson, a Scottish surgeon, along with Sir Paul Chater, Mr Phineas Ryrie, Mr Granville Sharp, Mr WH Ray and Mr JB Coughtry, five other prominent Hong Kong businessmen. The company was created with three founding objectives: to improve the health of Hong Kong people by providing them with non-contaminated cows' milk, to breed a herd of imported dairy cattle locally to decrease the price of milk by half, and to realise profit for its shareholders. Manson purchased 80 Friesian cows from Scotland and a plot of land for his farm in Pok Fu Lam. In 1890, Dairy Farm built a low-rise brick and stucco building on Lower Albert Road in Central for use as a cold storage warehouse. This warehouse was later renovated and expanded in 1913 to include a dairy shop, a room for meat smoking, a cold storage room for winter clothes and residency for its manager. The building later evolved into the company headquarters until the company moved in the 1970s. The abandoned building was acquired by the Hong Kong Fringe Club, a non-profit-making arts organisation in 1984, and has been carefully restored. This distinctive 19th century building, known as the Old Dairy Farm Depot, is a well-known landmark in Central providing a wide variety of cultural activities and performances.

== Structure == MCH is a cyclic 19-amino acid neuropeptide, as it is a polypeptide chain that is able to act as a neurotransmitter. MCH neurons are mainly concentrated in the lateral hypothalamic area, zona incerta, and the incerto-hypothalamic area, but they are also located, in much smaller amounts, in the paramedian pontine reticular formation (PPRF), medial preoptic area, laterodorsal tegmental nucleus, and the olfactory tubercle. MCH is activated by binding to two G-coupled protein receptors (GCPRs), MCHR1 and MCHR2. MCHR2 has only been identified in certain species such as humans, dogs, ferrets, and rhesus monkeys, while other mammals such as rodents and rabbits do not have the receptor. MCH is cleaved from prepro-MCH (ppMCH), a 165 amino acid polypeptide which also contains the neuropeptides GE and EI.

== Side effects == Eflornithine is not genotoxic; no tumour-inducing effects have been observed in carcinogenicity studies, including one photocarcinogenicity study. No teratogenic effects have been detected.

Sources: en.wikipedia.org

Reference notes

Aquino was assassinated at Manila International Airport (now Ninoy Aquino International Airport). September 1: Civilian Korean Air Lines Flight 007, with 269 passengers, including U.S. Congressman Larry McDonald, is shot down by Soviet interceptor aircraft. September 26: The 1983 Soviet nuclear false alarm incident occurs. The U.S.S.R. nuclear early warning system reports launch of multiple U.S. intercontinental ballistic missiles. Stanislav Yevgrafovich Petrov, an officer of the Soviet Air Defence Forces, correctly identifies them as false alarms. This decision is seen as having prevented a retaliatory nuclear attack based on erroneous data on the United States and its NATO allies, which likely would have resulted in nuclear war and the deaths of hundreds of millions of people. October 25: U.S. forces invade the Caribbean island of Grenada in an attempt to overthrow the Communist government, expel Cuban troops, and abort the construction of a Soviet-funded airstrip. November 2: Exercise Able Archer 83 – Soviet anti-aircraft misinterpret a test of NATO's nuclear warfare procedures as a fake cover for an actual NATO attack; in response, Soviet nuclear forces are put on high alert. December 10: The National Reorganization Process military junta of Argentina is dissolved by democratically elected president Raúl Alfonsín.

==== Corneal Allogenic Intrastromal Ring Segments (CAIRS) ==== Corneal Allogenic Intrastromal Ring Segments Keratoplasty (CAIRS Keratoplasty) represent an innovative surgical approach for the management of keratoconus, utilizing donor corneal tissue as biocompatible implants to reshape the ectatic cornea and improve visual acuity. CAIRS is a corneal transplant and due to its success rate, efficacy, safety profile and use of biologic tissue, it been recognised as such by funding bodies in Australia, the United Kingdom, Brazil, Japan, the Netherlands, Germany and numerous other countries. Unlike traditional synthetic intrastromal corneal ring segments (ICRS), which are typically made from polymethyl methacrylate (PMMA), CAIRS keratoplasty employs preserved allogeneic donor cornea to minimize risks such as extrusion, infection, or foreign body reactions associated with non-biological materials. The technique was developed by Soosan Jacob, who first described CAIRS in 2018 in a prospective interventional case series published in the Journal of Refractive Surgery. In this study, 24 eyes of 20 patients with keratoconus (grades 2–4) underwent CAIRS implantation combined with accelerated corneal collagen cross-linking (CXL). The procedure involved femtosecond laser-assisted creation of intrastromal tunnels followed by insertion of custom-cut allogeneic segments. Key outcomes included significant improvements in uncorrected distance visual acuity (UDVA) of 2.79 ± 2.65 lines and corrected distance visual acuity (CDVA) of 1.29 ± 1.33.

== Research and career == In 2000 Pohl joined the faculty at Iowa State University. She spent twelve years in Iowa, eventually being made Wilkinson Professor of Chemistry and Biomedical Engineering. In 2008 she founded LuCELLa Biosciences, a spin-out company who specialise in the custom synthesis of carbohydrates. Pohl joined Indiana University Bloomington in 2012, where she was made the Professor and Joan & Marvin Carmack Chair. Pohl is interested in the synthesis and characterisation of sugars in an effort to better understand their role in biological function. By better understanding the interactions of carbohydrates, Pohl believes that she will be able to rationally design vaccinations and other therapies. She demonstrated an oligosaccharide synthesis process that involved automated solution-phase methods. The automation process involves the use of fluorocarbon tags that can be used to pattern the surfaces of tagged molecules to form carbohydrate microarrays. Pohl spent 2019 as a Fulbright Program scholar at the University of Natural Resources and Life Sciences, Vienna.

Stoolmiller AC, Horwitz AL, Dorfman A (1972). "Biosynthesis of the chondroitin sulfate proteoglycan. Purification and properties of xylosyltransferase". J. Biol. Chem. 247 (11): 3525–32. doi:10.1016/S0021-9258(19)45172-7. PMID 5030630. Gotting C, Kuhn J, Zahn R, Brinkmann T, Kleesiek K (2000). "Molecular cloning and expression of human UDP-d-Xylose:proteoglycan core protein beta-d-xylosyltransferase and its first isoform XT-II". J. Mol. Biol. 304 (4): 517–28. doi:10.1006/jmbi.2000.4261. PMID 11099377.

Sources: en.wikipedia.org

Reference notes

Katy Higginson, lately Deputy Head, Royal and Coronation Unit, Foreign, Commonwealth and Development Office. For services to British Foreign Policy, to International Development, and to the Coronation of Their Majesties The King and The Queen. Dr Andi Hoxhaj, Lecturer in Law (Assistant Professor of Law), University College London. For services to UK/Albania Relations. Professor Alan Jamieson, Director, Deep Sea Centre, University of Western Australia. For services to Marine Biology, Subsea Engineering and Exploration. Dipak Karadia, Team Leader, Foreign, Commonwealth and Development Office. For services to National Security. Haifa Al Kaylani, President and Founder, Arab International Women's Forum. For services to women, to young people, and to cultural relations between the UK and the countries of the Middle East and North Africa region. Moses Kirkconnell III, Member of Parliament for Cayman Brac West and Little Cayman, Cayman Islands. For services to the Caymanian People, to the Tourism Industry, and to District Administration in the Cayman Islands. Gabrielle Kirstein, Founder and Chief Executive Officer, Feeding Hong Kong. For services to the community and tackling food waste and food poverty in Hong Kong. Leona Lewis, Singer-Songwriter, Performer and Philanthropist. For services to Music and to Charity. Sarah Lingard, lately Head of Events, Royal and Coronation Unit, Foreign, Commonwealth and Development Office. For services to British Foreign Policy and to the Coronation of Their Majesties The King and The Queen.

=== Macroscopic examination === Visual examination of the specimen may provide information to the pathologist or the physician. For example, fluid drained from an abscess may appear cloudy, or cerebrospinal fluid obtained by lumbar puncture may exhibit xanthochromia, suggesting a bleed has occurred. Laboratory technologists may provide qualitative descriptions accordingly.

=== Blood–brain barrier permeability === Beta blockers vary in their lipophilicity (fat solubility) and in turn in their ability to cross the blood–brain barrier and exert effects in the central nervous system. Beta blockers with greater blood–brain barrier permeability can have both neuropsychiatric therapeutic benefits and side effects, as well as adverse cognitive effects. Central nervous system-related side effects and risks of beta blockers may include fatigue, depression, sleep disorders (namely insomnia) and nightmares, visual hallucinations, delirium, psychosis, Parkinson's disease, and falling. Conversely, central nervous system-related benefits of beta blockers may include prevention and treatment of migraine, essential tremor, akathisia, anxiety, post-traumatic stress disorder, aggression, and obsessive–compulsive disorder. Most beta blockers are lipophilic and can cross into the brain, but there are a number of exceptions. Highly lipophilic beta blockers include penbutolol, pindolol, propranolol, and timolol, moderately lipophilic beta blockers include acebutolol, betaxolol, bisoprolol, carvedilol, metoprolol, and nebivolol, and low lipophilicity or hydrophilic beta blockers include atenolol, carteolol, esmolol, labetalol, nadolol, and sotalol. It is thought that highly lipophilic beta blockers are able to readily cross into the brain, moderately lipophilic beta blockers are able to cross to a lesser degree, and low lipophilicity or hydrophilic beta blockers are minimally able to cross.

=== Pharmacokinetics === Sirolimus is metabolized primarily by the CYP3A4 enzyme (about 90%), and to a lesser degree by CYP3A5 and CYP2C8. It is also a substrate of the P-glycoprotein (P-gp) efflux pump. It has linear pharmacokinetics. In studies on N=6 and N=36 subjects, peak concentration was obtained in 1.3 hours +/r- 0.5 hours and the terminal elimination was slow, with a half life around 60 hours +/- 10 hours. Sirolimus was not found to effect the concentration of ciclosporin, which is also metabolized primarily by the CYP3A4 enzyme. The bioavailabiliy of sirolimus is low, and the absorption of sirolimus into the blood stream from the intestine varies widely between patients, with some patients having up to eight times more exposure than others for the same dose. Drug levels are, therefore, taken to make sure patients get the right dose for their condition. This is determined by taking a blood sample before the next dose, which gives the trough level. However, good correlation is noted between trough concentration levels and drug exposure, known as area under the concentration-time curve, for both sirolimus (SRL) and tacrolimus (TAC) (SRL: r2 = 0.83; TAC: r2 = 0.82), so only one level need be taken to know its pharmacokinetic (PK) profile. PK profiles of SRL and of TAC are unaltered by simultaneous administration. Dose-corrected drug exposure of TAC correlates with SRL (r2 = 0.8), so patients have similar bioavailability of both.

In 2018 Stonewall described UK transgender healthcare as having "significant barriers to accessing treatment, including waiting times that stretch into years, far exceeding the maximums set by law for NHS patients". Patients have the legal right to begin treatment within 18 weeks of referral by their GP, however the average wait for patients to gender identity clinics was 18 months in 2020 with over 13,000 people on the waiting list for appointments at gender identity clinics. As of May 2024, prescription of puberty blockers to new patients under 18 for the treatment of gender dysphoria is banned for both private medical practices (by a law in parliament in May) and the official state healthcare National Health Service (NHS) which stopped their use earlier, in the aftermath of the Cass Review except for use in clinical research trials. Previously, on 30 June 2020, the NHS changed its website, replacing the statement that puberty blockers were "fully reversible" and that "treatment can usually be stopped at any time"; with "little is known about the long-term side effects of hormone or puberty blockers in children with gender dysphoria. The Bell v Tavistock decision by the High Court of Justice for England and Wales ruled children under 16 were not competent to give informed consent to puberty blockers, but this was overturned by the Court of Appeal in September 2021. In 2022, the British Medical Association opposed restrictions on puberty blockers, and the NHS restricted their use for children under 16 years of age to centrally administered clinical research.

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 is sample identity confirmed?

Mass spectrometry establishes whether the observed molecular weight matches the calculated sequence mass. Chromatographic retention and fragment mapping add further confidence about sequence and composition. A single technique alone is rarely treated as sufficient evidence of identity.

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