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Structure And Receptor Pharmacology — Background and Details

By Editorial Desk · published 2026-03-09 · last reviewed 2026-04-27 · Guide

The short version of lyophilized powder fits in a sentence. The long version — which is the one that helps — is below.

Reviewed 2026-04-27. Anything still debated is marked as such rather than presented as settled.

Structure And Receptor Pharmacology

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.

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.

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.

The compound emerged from work at a Canadian biotechnology firm in the early 2000s. Early human studies examined its effect on growth hormone and insulin-like growth factor 1 in healthy volunteers and in people with HIV-associated fat redistribution. Reports described sustained increases in both markers after a single injection. Development did not advance to regulatory approval, and the clinical programme was later discontinued. The molecule is now encountered mainly as a research chemical rather than a marketed medicine.

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

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.

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.

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Analytical Measurement And Stability

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.

Identity and purity are established with reversed phase high performance liquid chromatography coupled to mass spectrometry. The chromatographic step separates the target peptide from truncated sequences and deletion products, while the mass measurement confirms the expected molecular weight to within a fraction of a dalton. Because the two common variants differ by the presence of the linker, mass alone can distinguish them in the unconjugated state. Amino acid analysis and peptide mapping are used when sequence level confirmation is required.

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.

Reference notes

Progesterone is produced from cholesterol with pregnenolone as a metabolic intermediate. In the first step in the steroidogenic pathway, cholesterol is converted into pregnenolone, which serves as the precursor to the progestogens progesterone and 17α-hydroxyprogesterone. These progestogens, along with another steroid, 17α-hydroxypregnenolone, are the precursors of all other endogenous steroids, including the androgens, estrogens, glucocorticoids, mineralocorticoids, and neurosteroids. Thus, many tissues producing steroids, including the adrenal glands, testes, and ovaries, produce progestogens. In some tissues, the enzymes required for the final product are not all located in a single cell. For example, in ovarian follicles, cholesterol is converted to androstenedione, an androgen, in the theca cells, which is then further converted into estrogen in the granulosa cells. Fetal adrenal glands also produce pregnenolone in some species, which is converted into progesterone and estrogens by the placenta (see below). In the human, the fetal adrenals produce dehydroepiandrosterone (DHEA) via the pregnenolone pathway.

== Further reading == Rawlings ND, Barrett AJ, Bateman A. Asparagine peptide lyases: a seventh catalytic type of proteolytic enzymes. 2011 Nov 4;286(44):38321-8. Alan J. Barrett, Neil D. Rawlings, J. Fred (2012). Handbook of Proteolytic Enzymes. Third edition. ISBN 9780123822208 Guoyao Wu (2013) Amino Acids: Biochemistry and Nutrition. ISBN 9781439861899 Klaudia Brix, Walter Stöcker (Jan 21, 2014). Proteases: Structure and Function. ISBN 9783709108857 Jin Zhang, Sohum Mehta, Carsten Schultz (2016). Optical Probes in Biology. ISBN 9781466510128

== Adverse effects == As with other drugs that inhibit the renin–angiotensin system, if candesartan is taken by pregnant women during the second or third trimester, it can cause injury and in some cases, death of the developing fetus. Symptomatic hypotension may occur in people who take candesartan and are volume-depleted or salt-depleted, as can also occur when diuretics are coadministered. Reduction in renal glomerular filtration rate may occur; people with renal artery stenosis may be at higher risk. Hyperkalemia may occur; people who are also taking spironolactone or eplerenone may be at higher risk. Anemia may occur, due to inhibition of the renin–angiotensin system. As with other angiotensin receptor blockers, candesartan can rarely cause severe liver injury.

== Signs and symptoms == People with hypothyroidism often have no or only mild symptoms. Numerous signs and symptoms are associated with hypothyroidism and can be related to the underlying cause, or a direct effect of not having enough thyroid hormones. Many symptoms of hypothyroidism are otherwise common and do not necessarily indicate thyroid problem. Hashimoto's thyroiditis may present with the mass effect of a goiter (enlarged thyroid gland). In middle-aged women, the symptoms may be mistaken for those of menopause.

A metric foot, defined as 300 millimetres (approximately 11.8 inches), has been used occasionally in the UK but has never been an official unit. The corresponding metric inch of 25 millimetres (0.984 in) was used for pin spacing in Soviet microchips, which were often cloned from Western designs but scaled down slightly from US customary inches to metric inches. This led to incompatibility issues in the Soviet computer market.

Sources: en.wikipedia.org

Reference notes

MALDI/TOF serves as a method for determining the drug resistance of bacteria, especially to β-lactams (Penicillin family). The MALDI/TOF detects the presence of carbapenemases, which indicates drug resistance to standard antibiotics. It is predicted that this could serve as a method for identifying a bacterium as drug resistant in as little as three hours. This technique could help physicians decide whether to prescribe more aggressive antibiotics initially.

In August 2025, Moore's chief of staff, Fagan Harris, announced that he would resign his post at the end of the year to become the next president of the Abell Foundation; he was succeeded by Lester Davis, a CareFirst BlueCross BlueShield executive who worked as an unpaid outside advisor to Moore's 2022 gubernatorial campaign. In October 2025, Roland Butler resigned as secretary of state police and was succeeded by state senator Michael A. Jackson. In November 2025, Paul Monteiro resigned as secretary of Maryland Department of Service and Civic Innovation and was succeeded by Jonny Dorsey, one of Moore's deputy chiefs of staff. In October 2025, Moore appointed Walter Simmons to serve as the secretary of the newly created Department of Social and Economic Mobility. Two of Moore's cabinet secretaries resigned in 2026. Maryland Secretary of Human Services Rafael López, who resigned on February 23, citing health reasons, and was succeeded by deputy secretary Gloria Brown Burnett, who will serve as acting secretary until April 1, when Stacy Rodgers will then take over as acting secretary. In March 2026, Rai announced that he would step down on March 27, and would be succeeded by deputy secretary Elena Quiroz-Livanis, who will serve as acting secretary until a search for a new, permanent secretary is completed.

===== Clinical Laboratory Building ===== UPMC's nine-story Clinical Laboratory Building (CLB) opened in 2013 and cost $39 million. The CLB is located in the Oakland neighborhood and is situated between Magee-Womens Hospital and UPMC Presbyterian Hospital. Much of UPMC's laboratory testing is performed within the CLB. An extensive pneumatic tube system connects the CLB with UPMC hospitals that are in the Oakland neighborhood (Presbyterian, Magee-Womens, Montefiore) to facilitate the transport of specimens from the hospitals to the laboratories.

The exchange of a protecting group from a methyl ether to a MOM-ether inhibits here the opening of an epoxide to an aldehyde. Protecting group chemistry finds itself an important application in the automated synthesis of peptides and nucleosides. The technique was introduced in the field of peptide synthesis by Robert Bruce Merrifield in 1977. For peptide synthesis via automated machine, the orthogonality of the Fmoc group (basic cleavage), the tert‑butyl group (acidic cleavage) and diverse protecting groups for functional groups on the amino acid side-chains are used. Up to four different protecting groups per nucleobase are used for the automated synthesis of DNA and RNA sequences in the oligonucleotide synthesis. The procedure begins actually with redox chemistry at the protected phosphorus atom. A tricoordinate phosphorus, used on account of the high reactivity, is tagged with a cyanoethyl protecting group on a free oxygen. After the coupling step follows an oxidation to phosphate, whereby the protecting group stays attached. Free OH-groups, which did not react in the coupling step, are acetylated in an intermediate step. These additionally-introduced protecting groups then inhibit, that these OH-groups might couple in the next cycle.

Sources: en.wikipedia.org

Notes from published material

In a clinical trial, the rate of systolic orthostatic hypotension was 21% versus 9% with placebo and the rate of diastolic orthostatic hypotension was 12% versus 4% with placebo in people with Parkinson's disease taking the ODT form of selegiline. The risk of hypotension is greater at the start of treatment and in the elderly (3% vs. 0% with placebo). The rate of hypotension or orthostatic hypotension with the selegiline patch was 2.2% versus 0.5% with placebo in clinical trials of people with depression. Significant orthostatic blood pressure changes (≥10 mm Hg decrease) occurred in 9.8% versus 6.7% with placebo, but most of these cases were asymptomatic and heart rate was unchanged. The rates of other orthostatic hypotension-related side effects in this population were dizziness or vertigo 4.9% versus 3.1% with placebo and fainting 0.5% versus 0.0% with placebo. It is said that orthostatic hypotension is rarely seen with the selegiline transdermal patch compared to oral MAOIs. Caution is advised against rapidly rising after sitting or lying, especially after prolonged periods or at the start of treatment, as this can result in fainting. Falls are of particular concern in the elderly. MAOIs like selegiline may lower blood pressure by increasing dopamine levels and activating dopamine receptors, by increasing levels of the false neurotransmitter octopamine, and/or by other mechanisms. Meta-analyses published in the 1990s found that the addition of selegiline to levodopa increased mortality in people with Parkinson's disease.

=== August === 1 August – A study in Nature finds that based on current policies, there is a 45% risk of at least one major tipping point by 2300, even if global warming is brought back to below 1.5 °C. The risk is "strongly accelerated" for peak warming above 2.0 °C. The Atlantic Meridional Overturning Current (AMOC) is identified as being at the most urgent risk of collapse – possibly occurring as early as 2040 – followed by the Amazon rainforest in the 2070s. 5 August A study indicates vegetarian and vegan dog diets are healthier than both conventional meat and raw meat diets according to indicators like numbers of veterinary visits and reported veterinary assessment of being unwell, consistent with all related studies published to date. An analysis suggests hydraulic lifts may have been used to build ancient large Egyptian pyramids. 7 August – Scientists in Australia publish a new 400-year temperature reconstruction for the Coral Sea, showing that recent ocean heat has led to mass bleaching on the Great Barrier Reef. 8 August – A study on the terraforming of Mars suggests that releasing metal nanorods into the planet's atmosphere could warm it by 30 K, and would be far more efficient than trying to do so with greenhouse gases. 12 August Liquid water is confirmed to be present at depths of 10 to 20 km (6.2 to 12.4 mi) below the surface of Mars, based on a new analysis of data from NASA's InSight lander. An Earth-sized, ultra-short period exoplanet called TOI-6255b is found to be undergoing extreme tidal distortion, caused by the close proximity of its parent star.

=== 1970s === 1970: Australian geologist and palaeontologist Dorothy Hill became the first female president of the Australian Academy of Science. 1970: New Zealand geologist and palynologist Rosemary Askin the first New Zealand woman to undertake her own research programme in Antarctica. 1970: Spanish biochemist Margarita Salas discovered and characterized the Φ29 phage DNA polymerase. She was also the first scientific woman elected to the Royal Spanish Academy and was the first woman recipient of the Carlos J. Finlay Prize for Microbiology. 1970: Samira Islam became the first Saudi Arabian person to earn a PhD in pharmacology. 1970: American astronomer Vera Rubin published the first evidence for dark matter. 1970: Polish geologist Franciszka Szymakowska became widely known because of her unique and detailed geological drawings that are still used today. 1971: Romanian chemist Ecaterina Ciorănescu-Nenițescu became a member of the New York Chemical Society. She was noted for developing synthesis processes for antituberculosis drugs and insecticides and creating new substances using cytostatic grafting. 1973: American physicist Anna Coble became the first African-American woman to receive a PhD in biophysics, completing her dissertation at University of Illinois. 1974: Dominican marine biologist Idelisa Bonnelly founded the Dominican Republic Academy of Science. 1975: Indian chemist Asima Chatterjee was elected the General President of the Indian Science Congress Association. She simultaneously became the first female scientist ever elected a member of the congress.

glycogen(n residues) + Pi ⇌ glycogen(n-1 residues) + glucose-1-phosphate Here, glycogen phosphorylase cleaves the bond linking a terminal glucose residue to a glycogen branch by substitution of a phosphoryl group for the α[1→4] linkage. Glucose-1-phosphate is converted to glucose-6-phosphate (which often ends up in glycolysis) by the enzyme phosphoglucomutase. Glucose residues are phosphorolysed from branches of glycogen until four residues before a glucose that is branched with a α[1→6] linkage. Glycogen debranching enzyme then transfers three of the remaining four glucose units to the end of another glycogen branch. This exposes the α[1→6] branching point, which is hydrolysed by α[1→6] glucosidase, removing the final glucose residue of the branch as a molecule of glucose and eliminating the branch. This is the only case in which a glycogen metabolite is not glucose-1-phosphate. The glucose is subsequently phosphorylated to glucose-6-phosphate by hexokinase.

=== Brand names === In May 2015, a formulation of paliperidone palmitate was approved by the US Food and Drug Administration under the brand name Invega Trinza. A similar prolonged release suspension was approved in 2016 by the European Medicines Agency originally under the brand name Paliperidone Janssen, later renamed to Trevicta. In September 2021, a newer formulation of paliperidone palmitate, Invega Hafyera, was approved by the US FDA.

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.

What is CJC-1295?

It is a synthetic peptide analogue of growth hormone-releasing hormone. Four substitutions in its sequence make it more resistant to enzymatic degradation than the natural hormone. In the version carrying a drug affinity complex, the peptide binds albumin and remains in circulation for days.

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