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Structure And Receptor Pharmacology — Hands-On Walkthrough

By Editorial Desk · published 2026-06-08 · last reviewed 2026-07-30 · Data

CJC-1295 raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.

This page was last updated on 2026-07-30 and is reviewed periodically as new material appears.

Structure And Receptor Pharmacology

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.

Two related forms appear under the CJC-1295 name. The simpler analogue, commonly written as modified GRF(1-29), carries the four substitutions but no additional conjugation. The second form attaches a maleimidopropionic acid linker to a lysine residue, a modification frequently called the drug affinity complex. That linker reacts with the free thiol on serum albumin to form a covalent bond. Because albumin has a long residence time in blood, the conjugated peptide stays in circulation far longer than the unconjugated analogue.

Handling Storage And Analytical Methods

Research material is normally supplied as a freeze-dried powder in sealed vials. In that state the peptide is comparatively robust, but prolonged exposure to warmth, moisture, or light accelerates degradation. Storage at minus twenty degrees Celsius or lower, with desiccant and protection from light, is the commonly described practice. Vials should be allowed to reach room temperature before opening to limit condensation on the powder. Moisture uptake during handling is a recognized source of variability in later measurements.

Reconstitution is typically performed with sterile water or bacteriostatic water, added slowly against the vial wall. The resulting solution should be clear and colorless; cloudiness or visible particles suggest a problem with the material or the diluent. Once in solution, the peptide is less stable than the dry powder. Refrigerated storage at two to eight degrees Celsius is common for short-term holding, while freezing aliquots is described for longer periods.

Purity is most often assessed by reversed-phase high-performance liquid chromatography, reported as a percentage of total peak area. Identity is confirmed by mass spectrometry, which yields a molecular ion consistent with the expected sequence. Amino acid analysis and peptide mapping provide additional characterization. Reported purity values are method-dependent, so figures from different laboratories are not always directly comparable without details of column, gradient, and detection wavelength.

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

Albumin Binding and Duration of Action

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.

The distinguishing feature of the DAC form is a maleimide-containing group that reacts with the free thiol of cysteine-34 on human serum albumin. This reaction forms a covalent bond without enzymatic assistance, and it takes place after the peptide enters the bloodstream. Because albumin is abundant and long-lived, the attached peptide is carried through circulation far longer than an unmodified fragment would survive. The chemistry is a deliberate pharmacokinetic strategy rather than a change to receptor activity.

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.

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Background and Molecular Features

Two related peptides circulate under the CJC-1295 label, and they differ mainly in how long they persist in circulation. The version carrying a drug affinity complex includes a maleimidopropionic acid linker that forms a covalent bond with serum albumin. The other version, usually written as modified GRF(1-29) or tetrasubstituted GRF(1-29), lacks that linker and is cleared quickly. Mixing the two produces inconsistent readings of published half-life values, because the linker rather than the receptor-facing sequence drives most of the difference.

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.

Receptor Action and Pharmacokinetics

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.

Background and Naming Conventions

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.

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.

Further detail

The special forces site, located near a compound associated with Mullah Omar, was described as one of Akhundzada's most trusted units. Afghan locals also reported an airstrike in Spin Boldak District, while armed clashes resumed between Taliban forces and Pakistani border guards in Khost. However, a Taliban spokesperson claimed that no one had been hurt in the airstrikes and that they had caused only limited damage to a drug rehabilitation centre and an empty container. A police constable was injured while repelling a militant attack on a police post in Dera Ismail Khan District.

== History == The word esophagus (British English: oesophagus), comes from the Greek: οἰσοφάγος (oisophagos) meaning gullet. It derives from two roots (eosin) to carry and (phagos) to eat. The use of the word esophagus, has been documented in anatomical literature since at least the time of Hippocrates, who noted that "the oesophagus ... receives the greatest amount of what we consume." Its existence in other animals and its relationship with the stomach was documented by the Roman naturalist Pliny the Elder (AD23–AD79), and the peristaltic contractions of the esophagus have been documented since at least the time of Galen. The first attempt at surgery on the esophagus focused in the neck, and was conducted in dogs by Theodore Billroth in 1871. In 1877 Czerny carried out surgery in people. By 1908, an operation had been performed by Voeckler to remove the esophagus, and in 1933 the first surgical removal of parts of the lower esophagus, (to control esophageal cancer), had been conducted. The Nissen fundoplication, in which the stomach is wrapped around the lower esophageal sphincter to stimulate its function and control reflux, was first conducted by Rudolph Nissen in 1955.

== Sources == Schaffer, Phillip Otto Folin: (1867–1934) (Journal of Nutrition. volume 52, issue 1, pages 3–11. 1954) [1] Edsall, John T. A Biomedical Pioneer (Science, volume 244 (4905), pages 719–720. 1989, doi 10.1126/science.244.4905.719)

Digoxin (wherein it may result in increased serum digoxin levels) Insulin or anti-diabetic medication (wherein it may enhance the effects of a hypoglycemic treatment) Drugs that prolong the QT interval such as methadone, and other arrhythmogenic drugs, as hydroxychloroquine prolongs the QT interval and may increase the risk of inducing serious abnormal heart rhythms (ventricular arrhythmias) if used concurrently. Mefloquine and other drugs known to lower the seizure threshold (co-administration with other antimalarials known to lower the convulsion threshold may increase risk of convulsions) Antiepileptics (concurrent use may impair the antiepileptic activity) Methotrexate (combined use is unstudied and may increase the frequency of side effects) Cyclosporin (wherein an increased plasma cyclosporin level was reported when used together).

Sources: en.wikipedia.org

Supporting material

is the chemical potential in the standard state, R is the gas constant T is the absolute temperature, and Aj is the activity. For a closed system, no particles may enter or leave, although they may combine in various ways. The total number of atoms of each element will remain constant. This means that the minimization above must be subjected to the constraints:

26 May to 7 November The 1st Marine Division, ARVN 51st Regiment and Republic of Korea Marine Corps 2nd Marine Brigade launch Operation Pipestone Canyon to pacify and clear Go Noi Island, Quảng Nam Province. The operation results in 852 PAVN/VC killed and 58 captured, U.S. Marine losses were 71 killed.

== The control charts == Control charts are a statistical approach to the study of manufacturing process variation for the purpose of improving the economic effectiveness of the process. These methods are based on continuous monitoring of process variation. The control chart, also known as the Shewhart chart or process-behavior chart, is a statistical tool intended to assess the nature of variation in a process and to facilitate forecasting and management. A control chart is a more specific kind of run chart. The control chart is one of the seven basic tools of quality control, which also include the histogram, pareto chart, check sheet, cause and effect diagram, flowchart and scatter diagram. Control charts prevent unnecessary process adjustments, provide information about process capability, provide diagnostic information, and are a proven technique for improving productivity.

== History == CPA was first synthesized in 1961 by Rudolf Wiechert, a Schering employee, and together with Friedmund Neumann in Berlin, they filed for a patent for CPA as "progestational agent" in 1962. The antiandrogenic activity of CPA was discovered serendipitously by Hamada, Neumann, and Karl Junkmann in 1963. Along with the steroidal antiandrogens benorterone (17α-methyl-B-nortestosterone; SKF-7690), cyproterone, BOMT (Ro 7–2340), and trimethyltrienolone (R-2956) and the nonsteroidal antiandrogens flutamide and DIMP (Ro 7–8117), CPA was one of the first antiandrogens to be discovered and researched. CPA was initially developed as a progestogen for the prevention of threatened abortion. As part of its development, it was assessed for androgenic activity to ensure that it would not produce teratogenic effects in female fetuses. The drug was administered to pregnant rats and its effects on the rat fetuses were studied. To the surprise of the researchers, all of the rat pups born appeared to be female. After 20 female rat pups in a row had been counted, it was clear that this could not be a chance occurrence. The rat pups were further evaluated and it was found that, in terms of karyotype, about 50% were actually males. The male rat pups had been feminized, and this resultant finding constituted the discovery of the powerful antiandrogenic activity of CPA. A year after patent approval in 1965, Neumann published additional evidence of CPA's antiandrogenic effect in rats; he reported an "organizational effect of CPA on the brain".

Testosterone was marketed as a suppository for rectal administration by Ferring Pharmaceuticals from the early 1960s under brand names such as Rektandron and Testosteron. Rectal administration of testosterone avoids the first-pass effect with oral administration similarly to other non-oral routes. A single 40 mg dose of rectal testosterone has been found to result in maximal testosterone levels of almost 1,200 ng/dL within 30 minutes. Subsequently, testosterone levels steadily decline, reaching levels of about 700 ng/dL after 4 hours and levels of about 400 ng/dL after 8 hours. Other studies have also assessed the use of rectal testosterone, with similar findings. Rectal use of testosterone requires administration two or three times per day to maintain adequate testosterone levels. The route is poorly accepted, owing to its inconvenience. Rectal testosterone has been used in transmasculine hormone therapy.

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 should the dry powder be stored?

Cool, dark, and dry conditions are standard, with storage at minus twenty degrees Celsius or below. Desiccant and sealed vials limit moisture uptake. Repeated warming and cooling of the container is generally avoided.

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