purity 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 2025-10-27 and is reviewed periodically as new material appears.
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.
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.
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.
Stability depends heavily on physical state. A lyophilized powder kept dry, desiccated, and shielded from light typically holds its integrity for months to years at minus twenty degrees Celsius, and longer at minus eighty. Once dissolved, the peptide becomes far more vulnerable, since peptide bond hydrolysis, oxidation of susceptible residues, and aggregation all proceed faster in solution. Buffers near neutral pH are generally gentler than strongly acidic or alkaline conditions. Repeated freeze-thaw cycles and exposure to air-liquid interfaces during vigorous mixing cause losses that are easy to overlook.
| Property | Value | Notes |
|---|---|---|
| Molecular weight, DAC form | About 3647 Da | Varies with salt form |
| Molecular weight, non-DAC form | About 3358 Da | MOD GRF(1-29) |
| Solubility class | Water soluble | Also dissolves in polar solvents |
| Reported half-life, DAC form | About five to eight days | Values from human studies |
| Common synonyms | CJC-1295; MOD GRF(1-29) | Name depends on variant |
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.
Lyophilized material is typically stored at minus twenty degrees Celsius or lower. Keeping the vial dry and protected from light preserves peptide integrity. Repeated freeze-thaw cycles can cause aggregation or loss of activity. Once dissolved, solutions are generally kept at two to eight degrees Celsius. Stability data for reconstituted solutions vary, and long-term behavior is not fully established. Working aliquots reduce the number of times a stock container is opened.
Reverse-phase high-performance liquid chromatography is the standard tool for purity assessment. The technique separates the target peptide from truncated or modified byproducts. Mass spectrometry confirms molecular weight and supports sequence verification. Electrospray ionization and matrix-assisted laser desorption are both used. Amino acid analysis provides an independent check on composition. Purity values are commonly reported as area percentage from the chromatogram. Residual trifluoroacetate and water content are also measured in many quality programs.
Lyophilised powder is the usual supplied form. The material is hygroscopic, so vials are typically equilibrated to room temperature before opening in order to prevent condensation on the contents. Long-term storage is generally described at minus twenty degrees Celsius or colder, protected from light and moisture. Repeated freeze-thaw cycles are avoided because they promote aggregation and loss of soluble material. A reconstituted solution is considerably less stable than the dry powder and is normally kept refrigerated for short periods only.
Identity and purity are assessed mainly by reversed-phase high-performance liquid chromatography combined with mass spectrometry. The chromatographic separation resolves the target peptide from truncation products and from species carrying oxidised residues, while mass measurement confirms the expected molecular mass. Because the two common variants differ by roughly 280 daltons, a mass determination distinguishes them unambiguously. Purity is often quoted as a percentage of total peak area, although that figure depends on the detection wavelength and the integration method applied.
Reported half-lives differ widely between the two variants and between species. Values for the albumin-binding form are usually expressed in days, while the unconjugated form is measured in minutes to a few hours. Sampling schedules, assay sensitivity, and route of administration all influence the numbers, which limits direct comparison across studies. Whether sustained receptor occupancy produces different downstream effects from pulsatile stimulation remains an open question in the published work. Claims about relative potency should therefore be read alongside the specific study design that produced them.
=== Wirkungsmechanismus === Desipramin ist der aktive Metabolit von Imipramin. Es wirkt im zentralen Nervensystem und hemmt die Wiederaufnahme von Serotonin, Noradrenalin und weiterer Neurotransmitter aus dem synaptischen Spalt in die präsynaptischen Vesikel, wodurch deren Konzentration angehoben wird und depressive Symptome gemildert werden. Die sedierende Wirkkomponente ist schwach ausgeprägt. Ferner unterdrückt Desipramin die Schmerzwahrnehmung durch Wirkung an den Nozizeptoren (antinozizeptive Wirkung). Desipramin wirkt zudem als FIASMA (funktioneller Hemmer der sauren Sphingomyelinase).
=== Nebenwirkungen === Die häufigsten unerwünschten Wirkungen des Desipramins wie etwa Störungen beim Wasserlassen (Miktionsstörungen), innere Unruhe und Durstgefühl wie auch gelegentlich zu beobachtende unerwünschten Wirkungen wie Verwirrtheitszustände, Darmlähmung oder -verschluss (paralytischer Ileus) und Harnverhaltung resultieren aus seiner anticholinergen Wirkung. Desipramin kann die QT-Zeit des Elektrokardiogramms (EKG) verlängern bis hin zu einer gefährlichen Herzrhythmusstörung, der Torsade de pointes. Ein frischer Herzinfarkt, höhergradige AV-Blockierungen und andere Herzrhythmusstörungen sind daher Gegenanzeigen für eine Behandlung mit Desipramin. Die US-amerikanische Behörde Food and Drug Administration (FDA) ordnete im Dezember 2009 die Aufnahme eines Warnhinweises in die Produktfachinformation von Norpramin an hinsichtlich einer besonders vorsichtigen Behandlung von Patienten, in deren familiärer Krankheitsvorgeschichte Vorfälle wie plötzlicher Herztod, Herzrhythmusstörungen oder Herzleitungsstörungen auftraten. Für einige trizyklische Antidepressiva incl. Desipramin wird eine Erhöhung des Brustkrebsrisikos diskutiert, wobei eine Reihe von Übersichtsarbeiten und Metaanalysen diese Hypothese nicht bestätigen konnten.
=== Wechselwirkungen === Die Wirkungen von Desipramin und von Alkohol sowie anderen zentral wirksamen Arzneistoffen (Barbiturate, Schmerzmittel, Antihistaminika, Antipsychotika) können sich gegenseitig verstärken. Auch tritt Desipramin in Wechselwirkung mit Stoffen, die an gleichen Rezeptoren angreifen (Anticholinergika, Serotonin-Wiederaufnahmehemmer (SRI), α-Sympathomimetika), die QT-Zeit im EKG verlängern (beispielsweise bestimmte Antiarrhythmika, Antibiotika, Malaria-Mittel, Neuroleptika) oder die die Verstoffwechselung von Desipramin beeinflussen. Kontraindiziert ist die gleichzeitige Behandlung mit MAO-Hemmern, da schwerwiegende unerwünschte Wirkungen auftreten können. Zwischen Behandlungen mit Desipramin und MAO-Hemmern ist jeweils eine therapiefreie Zeit (Auswaschphase) einzuhalten.
=== Pharmakokinetik === Desipramin wird gut aus dem Darm resorbiert, hat aber aufgrund seines hohen First-Pass-Effektes eine erniedrigte Bioverfügbarkeit, die zudem stark schwanken kann. Die Plasmahalbwertszeit beträgt 15 bis 25 Stunden. Desipramin passiert die Blut-Hirn- und die Plazentaschranke und tritt in die Muttermilch über. Desipramin wird nach Biotransformation in der Leber über die Nieren (renal) ausgeschieden.
Sources: de.wikipedia.org
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.
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.
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.
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.