This is a working overview of DAC, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-06-21 and is reviewed periodically as new material appears.
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.
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.
Lyophilized peptide powder is comparatively stable when kept dry, cold, and protected from light. Once dissolved, the molecule is vulnerable to deamidation, oxidation, and aggregation, with the rate depending on pH, buffer composition, and temperature. Alkaline conditions and repeated freeze-thaw cycles accelerate loss of the intact peptide. The methionine present in the native sequence is a known oxidation site, which is one reason it was replaced in the modified fragment. Suppliers typically recommend cold storage of solutions and use within a short window.
Analytical confirmation usually relies on reversed-phase high-performance liquid chromatography for purity and on liquid chromatography coupled to mass spectrometry for identity. Mass data reveal the expected molecular mass and can flag truncated or oxidized species. Amino acid analysis and peptide mapping provide sequence-level verification. Immunoassays are used in some biological matrices, but antibodies raised against one releasing-hormone analog may cross-react with another. Reported purity figures depend heavily on the method used, so comparisons between suppliers require matching the analytical approach.
| Property | Value | Notes |
|---|---|---|
| Physical form | Lyophilized white powder | Supplied as a freeze-dried solid for research use |
| Molecular weight | Approximately 3,647 Da (DAC form) | Lower for the variant lacking the albumin-binding moiety |
| Solubility | Soluble in water and aqueous buffer | Typically dissolved in sterile or bacteriostatic water |
| Typical storage temperature | −20 °C or below | Dry powder, desiccated and protected from light |
| Common analytical method | Reversed-phase HPLC with mass spectrometry | Used for purity estimation and identity confirmation |
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.
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.
In this trial, at Week 16, subjects previously receiving placebo were re-randomized to receive abrocitinib 100 mg or 200 mg, subjects previously receiving abrocitinib continued on their respective dose and subjects previously receiving dupilumab continued to take placebo.
The FDA has identified that breast implants may be associated with a rare form of cancer called anaplastic large-cell lymphoma (ALCL), which some experts believe is believed to be associated with chronic bacterial inflammation. Similar ALCL phenomena have been seen with other types of medical implants including vascular access ports, orthopedic hip implants, and jaw (TMJ) implants. The causal association between breast implants and ALCL was conclusively established in December 2013, when researchers at MD Anderson Cancer Center published a study of 60 women with breast implants who were diagnosed with ALCL in the breast. In 2015, plastic surgeons published an article reviewing 37 articles in the literature on 79 patients and collected another 94 unreported cases, resulting in 173 women with breast implants who had developed ALCL of the breast. They concluded that "Breast implant-associated ALCL is a novel manifestation of site- and material-specific lymphoma originating in a specific scar location, presenting a wide array of diverse characteristics and suggesting a multifactorial cause." They stated that "There was no preference for saline or silicone fill or for cosmetic or reconstructive indications." Where implant history was known, the patient had received at least one textured-surface device. In 2016, the World Health Organization (WHO) officially recognized BIA-ALCL. As of April 2022, the FDA has received 1,130 global medical device reports (MDRs) of BIA-ALCL, including 59 deaths.
In astronomy, the term spectrophotometry refers to the measurement of the spectrum of a celestial object in which the flux scale of the spectrum is calibrated as a function of wavelength, usually by comparison with an observation of a spectrophotometric standard star, and corrected for the absorption of light by the Earth's atmosphere.
The instrumentation needed to perform capillary electrophoresis is relatively simple. A basic schematic of a capillary electrophoresis system is shown in figure 1. The system's main components are a sample vial, source and destination vials, a capillary, electrodes, a high-voltage power supply, a detector, and a data output and handling device. The source vial, destination vial and capillary are filled with an electrolyte such as an aqueous buffer solution. To introduce the sample, the capillary inlet is placed into a vial containing the sample. Sample is introduced into the capillary via capillary action, pressure, siphoning, or electrokinetically, and the capillary is then returned to the source vial. The migration of the analytes is initiated by an electric field that is applied between the source and destination vials and is supplied to the electrodes by the high-voltage power supply. In the most common mode of CE, all ions, positive or negative, are pulled through the capillary in the same direction by electroosmotic flow. The analytes separate as they migrate due to their electrophoretic mobility, and are detected near the outlet end of the capillary. The output of the detector is sent to a data output and handling device such as an integrator or computer. The data is then displayed as an electropherogram, which reports detector response as a function of time. Separated chemical compounds appear as peaks with different migration times in an electropherogram. The technique is often attributed to James W.
Sources: en.wikipedia.org
== Subsidiaries == Following declining earnings in 1965, HVEC reorganized into profit centers and established three wholly owned subsidiaries to diversify beyond particle accelerators. After U.S. orders for new accelerators ceased in the early 1970s, HVEC transformed into a miniconglomerate with more than ten subsidiaries, and industrial products from these units accounted for 80 percent of company revenues by 1972.
== Interactions == Even in the form of eye drops, levebunolol may cause hypotension when combined with alpha blockers, calcium channel blockers, tricyclic antidepressants, and other drugs that lower blood pressure. It can also cause severe hypertension (high blood pressure) when combined with sympathomimetic drugs or MAO-A inhibitors, bradycardia (low heart rate) when combined with antiarrhythmics or mefloquine, and hypoglycemia (low blood sugar) when combined with antidiabetic drugs such as insulin.
=== June === 21 June – Ahead of the unfolding secret payment scandal, the Director General of RTÉ, Dee Forbes, was suspended from her employment by the RTÉ Board, and later issued a statement defending her record. 22 June The postal service An Post moved from its historic headquarters in the General Post Office building on O'Connell Street in Dublin to new premises at North Wall Quay. RTÉ admitted that it paid its top presenter Ryan Tubridy €345,000 more than publicly declared between 2017 and 2022, in what the chair of its board said was a "serious breach of trust with the public". 24 June – All 30 remaining Argos retail stores in Ireland closed permanently. 25 June – Phase 5a of the BusConnects transport infrastructure programme was launched in Dublin 26 June – Dee Forbes resigned as Director-General of RTÉ with immediate effect, following ongoing controversy over undisclosed payments to broadcaster Ryan Tubridy.
=== Genetic labeling === Fluorescence in situ hybridization (FISH), is an example of a genetic labeling technique that utilizes probes that are specific for chromosomal sites along the length of a chromosome, also known as chromosome painting. Multiple fluorescent dyes that each have a distinct excitation and emission wavelength are bound to a probe which is then hybridized to chromosomes. A fluorescence microscope can detect the dyes present and send it to a computer that can reveal the karyotype of a cell. This technique allows abnormalities such as deletions and duplications to be revealed.
The transition from wakefulness to sleep (REM sleep or NREM sleep) is associated with a reduction in upper-airway muscle tone. During REM sleep, the muscle tone of the throat and neck, as well as that of the vast majority of skeletal muscles, is almost completely relaxed. This allows the tongue and soft palate/oropharynx to relax, reducing airway patency and potentially impeding or completely obstructing air flow into the lungs during inspiration, resulting in reduced respiratory ventilation. If reductions in ventilation are associated with sufficiently low blood-oxygen levels or with sufficiently high breathing efforts against an obstructed airway, neurological mechanisms may trigger a sudden interruption of sleep, called a neurological arousal. This arousal can cause an individual to gasp for air and awaken. These arousals rarely result in complete awakening but can have a significant negative effect on the restorative quality of sleep. In significant cases of OSA, one consequence is sleep deprivation resulting from the repetitive disruption and recovery of sleep activity. This sleep interruption in Stage 3 NREM sleep (also called slow-wave sleep) and in REM sleep can interfere with normal growth patterns, healing, and immune response, especially in children and young adults. The fundamental cause of OSA is a blocked upper airway, usually behind the tongue and epiglottis, whereby the otherwise patent airway, in an erect, awake patient, collapses when the patient lies on his or her back and loses muscle tone upon entering deep sleep.
Sources: en.wikipedia.org
A soft-tissue sarcoma (STS) is a malignant tumor, a type of cancer, that develops in soft tissue. A soft-tissue sarcoma is often a painless mass that grows slowly over months or years. They may be superficial or deep-seated. Any such unexplained mass must be diagnosed by biopsy. Treatment may include surgery, radiotherapy, chemotherapy, and targeted drug therapy. Bone sarcomas are the other class of sarcomas. There are many different types, many of which are rarely found. The World Health Organization lists more than fifty subtypes.
== History == Creatine was first identified in 1832 when Michel Eugène Chevreul isolated the precipitate from the basified water-extract of skeletal muscle. He later named the crystallized precipitate after the Greek word for meat, κρέας (kreas). In 1928, creatine was shown to exist in equilibrium with creatinine. Studies in the 1920s showed that consumption of large amounts of creatine did not result in its excretion. This result pointed to the ability of the body to store creatine, which in turn suggested its use as a dietary supplement. In 1912, Harvard University researchers Otto Folin and Willey Glover Denis found evidence that ingesting creatine can dramatically boost the creatine content of the muscle. The discovery of phosphocreatine was reported in 1927. In the 1960s, the enzyme creatine kinase was shown to phosphorylate ADP using phosphocreatine to generate ATP and thus buffering the ATP/ADP ratio. While creatine's influence on physical performance has been well documented since the early twentieth century, it came into public view following the 1992 Olympics in Barcelona. An 7 August 1992 article in The Times reported that Linford Christie, the gold medal winner at 100 metres, had used creatine before the Olympics. An article in Bodybuilding Monthly named Sally Gunnell, who was the gold medalist in the 400-metre hurdles, as another creatine user. In addition, The Times also noted that 110 metre hurdler Colin Jackson began taking creatine before the Olympics.
==== 1917: British-Zionist formal negotiations ==== Following the change in government, Sykes was promoted into the War Cabinet Secretariat with responsibility for Middle Eastern affairs. In January 1917, despite having previously built a relationship with Moses Gaster, he began looking to meet other Zionist leaders; by the end of the month he had been introduced to Weizmann and his associate Nahum Sokolow, a journalist and executive of the World Zionist Organization who had moved to Britain at the beginning of the war. On 7 February 1917, Sykes, claiming to be acting in a private capacity, entered into substantive discussions with the Zionist leadership. The previous British correspondence with "the Arabs" was discussed at the meeting; Sokolow's notes record Sykes's description that "The Arabs professed that language must be the measure [by which control of Palestine should be determined] and [by that measure] could claim all Syria and Palestine. Still the Arabs could be managed, particularly if they received Jewish support in other matters." At this point the Zionists were still unaware of the Sykes–Picot Agreement, although they had their suspicions. One of Sykes's goals was the mobilization of Zionism to the cause of British suzerainty in Palestine, so as to have arguments to put to France in support of that objective.
dopaquinone → leucodopachrome → dopachrome → 5,6-dihydroxyindole-2-carboxylic acid → quinone → eumelanin dopaquinone → leucodopachrome → dopachrome → 5,6-dihydroxyindole → quinone → eumelanin Detailed metabolic pathways can be found in the KEGG database (see External links).
Sources: en.wikipedia.org
The two share the same 29-amino-acid backbone. CJC-1295 carries an additional albumin-binding moiety that markedly extends its residence time in circulation, while the form without that moiety clears faster. Literature sometimes applies the name loosely to either variant.
It has not been approved by major regulatory agencies for any therapeutic indication. Material sold under this name is typically distributed for laboratory research only. Clinical use is not supported by large controlled trials.
Early human studies of the albumin-binding form reported circulation half-lives on the order of several days. The value depends on assay method and study design. Estimates for the form without the binding moiety are considerably shorter.
The version carrying the affinity complex bears a maleimide group that binds serum albumin, which extends its circulation time to several days. The version without it lacks this group and clears within roughly half an hour. The two are chemically related but behave very differently once in the body.