DAC 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.
Last reviewed on 2026-06-21. Where a claim depends on a specific study, the study is described rather than over-claimed.
Reports on this compound commonly follow serum growth hormone and insulin-like growth factor 1 across defined time windows. Protocols differ in sampling frequency, assay platform, and participant characteristics, which makes direct comparison between publications difficult. Some work focuses on pulsatile release patterns instead of average concentrations. Whether repeated exposure alters endogenous hormone rhythms over long periods remains an open question, and the formal literature is thinner than the volume of informal commentary implies.
Once in circulation, the peptide binds the growth hormone-releasing hormone receptor displayed on pituitary somatotroph cells. Receptor activation couples to Gs proteins, elevates intracellular cyclic AMP, and drives protein kinase A signaling inside the cell. That cascade increases discharge of growth hormone into the bloodstream. The analog therefore operates through a receptor pathway that already exists for the body's own releasing hormone, rather than through an engineered artificial target.
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.
| Property | Value | Notes |
|---|---|---|
| Primary target | GHRH receptor | Present on pituitary somatotroph cells |
| Signal pathway | Gs, cyclic AMP, protein kinase A | Sequence follows receptor activation |
| Main measured effect | Growth hormone release | Insulin-like growth factor 1 shifts indirectly |
| Half-life, binding form | Several days | Extended through serum albumin association |
| Half-life, unmodified form | About 30 minutes | Limited mainly by enzymatic cleavage |
Two related forms circulate in technical discussion under the same family name. The original version carries a drug affinity complex (DAC) that binds covalently to serum albumin after administration, and this linkage substantially extends circulation time. A second form, frequently written as modified GRF(1-29) or CJC-1295 without DAC, lacks that linker and clears much faster. The naming is a frequent source of confusion because the shorthand CJC-1295 can refer to either form depending on the source. Reports sometimes fail to specify which variant was studied.
The peptide backbone includes a D-alanine at position two, which resists cleavage by dipeptidyl peptidase IV, and several other substitutions that reduce degradation. Its molecular weight is roughly 3.4 kDa without the linker and about 3.6 kDa with it. The molecule is water soluble and is normally supplied as a lyophilized powder. Precise sequence and mass values depend on which variant is described, so technical documents usually state the exact form being referenced.
CJC-1295 is a synthetic peptide designed as a long-acting analogue of growth hormone-releasing hormone (GHRH). Its structure derives from the first 29 amino acids of native GHRH, a fragment often called GRF(1-29). Four substitutions were introduced to slow enzymatic breakdown and extend activity relative to the natural sequence. The compound was developed by ConjuChem as part of a broader effort to improve the pharmacokinetic profile of peptide hormones. It is studied in laboratory and clinical research settings rather than appearing as a naturally occurring substance.
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.
Two principal forms appear in the literature and in research supply. One carries a drug affinity complex, a maleimide-based group that forms a covalent bond with circulating albumin. This linkage slows clearance and produces a long-lasting elevation of peptide levels. The other form lacks that group and is often labeled MOD GRF(1-29). It has a much shorter circulation time. Both variants retain the same core receptor-binding sequence. Reported half-lives differ substantially between the two.
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.
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.
Lyophilized material is generally stable for extended periods when held at minus twenty degrees Celsius or below and protected from moisture and light. In solution the peptide is more labile; bond hydrolysis, aggregation and oxidation of susceptible residues all proceed faster at ambient temperature. Repeated freeze and thaw cycles should be avoided because they promote clumping and loss of soluble material. The conjugated variant adds a further consideration, since the maleimide group can hydrolyze in aqueous buffer and lose its ability to react with albumin.
== Analysis == In simple manual columns, the eluent is collected in constant volumes, known as fractions. The more similar the particles are in size the more likely they are in the same fraction and not detected separately. More advanced columns overcome this problem by constantly monitoring the eluent.
The laser at the other end of the light channel was to be set in an adjustable frame such that its beam could track across the width of the fiber bundle, allowing it to brand simple designs on the fish. Farrell also validated the method for Dungeness crabs in 1973. At a 1975 symposium, Farrell reported success in using freeze brands as a form of cryotherapy to treat various animal tumors. The greater mass of freeze brands was thought to render them more effective at destroying diseased or malignant tissue than conventional human cryotherapy, in which a coolant such as freon or liquid nitrogen is sprayed directly on the patient's skin. He lists malignant and nonmalignant tumors as both having been successfully treated with applications of freeze brands. Other conditions Farrell reported as successfully treated in this way include myxosarcoma, hemangiosarcoma, squamous cell carcinoma, adenoma, melanoma, fibroma, equine sarcoids, atheroma, granuloma, capped hock hygroma, and chronic fistulous tracts. One of the more unusual uses for freeze branding was also described at this meeting: permanently descending skunks and billy goats.
Major production sites include Sulawesi, Indonesia, the Sudbury region of Canada, New Caledonia in the Pacific, Western Australia, and Norilsk, Russia. Nickel is one of four elements (the others are iron, cobalt, and gadolinium) that are ferromagnetic at about room temperature. Alnico permanent magnets based partly on nickel are of intermediate strength between iron-based permanent magnets and rare-earth magnets. The metal is used chiefly in alloys and corrosion-resistant plating. About 68% of world production is used in stainless steel. A further 10% is used for nickel-based and copper-based alloys, 9% for plating, 7% for alloy steels, 3% in foundries, and 4% in other applications such as in rechargeable batteries, including those in electric vehicles (EVs). Nickel is widely used in coins, though nickel-plated objects sometimes provoke nickel allergy. As a compound, nickel has a number of niche chemical manufacturing uses, such as a catalyst for hydrogenation, cathodes for rechargeable batteries, pigments and metal surface treatments. Nickel is an essential nutrient for some microorganisms and plants that have enzymes with nickel as an active site.
In molecular biology, extracellular signal-regulated kinases (ERKs) or classical MAP kinases are widely expressed protein kinase intracellular signalling molecules that are involved in functions including the regulation of meiosis, mitosis, and postmitotic functions in differentiated cells. Many different stimuli, including growth factors, cytokines, virus infection, ligands for heterotrimeric G protein-coupled receptors, transforming agents, and carcinogens, activate the ERK pathway. The term, "extracellular signal-regulated kinases", is sometimes used as a synonym for mitogen-activated protein kinase (MAPK), but has more recently been adopted for a specific subset of the mammalian MAPK family. In the MAPK/ERK pathway, Ras activates c-Raf, which in turn phosphorylates a mitogen-activated protein kinase kinase (abbreviated as MKK, MEK, or MAP2K), which subsequently phosphorylates one or more ERKs, such as MAPK1/2 (below). Ras is typically activated by growth hormones through receptor tyrosine kinases and GRB2/SOS, but may also be activated by other signals. ERKs can activate many transcription factors, such as ELK1, and other downstream protein kinases. Disruption of the ERK pathway commonly leads to cancers, especially when caused by mutations in Ras, c-Raf, or receptors such as HER2.
=== Differential diagnosis === The major differential diagnosis is diabetic ketoacidosis (DKA). In contrast to DKA, serum glucose levels in HHS are extremely high, usually greater than 40-50 mmol/L (600 mg/dL). Metabolic acidosis is absent or mild. A temporary state of confusion (delirium) is also more common in HHS than DKA. HHS also tends to affect older people more. DKA may have fruity breath, and rapid and deep breathing. DKA often has serum glucose level greater than 300 mg/dL (HHS is >600 mg/dL). DKA usually occurs in type 1 diabetics whereas HHS is more common in type 2 diabetics. DKA is characterized by a rapid onset, and HHS occurs gradually over a few days. DKA also is characterized by ketosis due to the breakdown of fat for energy. Both DKA and HHS may show symptoms of dehydration, increased thirst, increased urination, increased hunger, weight loss, nausea, vomiting, abdominal pain, blurred vision, headaches, weakness, and low blood pressure with standing.
Sources: en.wikipedia.org
Hormonal imbalance (elevated ratio of estrogen to androgen) during early puberty, either due to decreased androgen production from the adrenals and/or increased conversion of androgens to estrogens, leads to transient gynecomastia in adolescent males. It can occur in up to 65% of adolescents as early as age 10 and peaks at ages 13 and 14. It is self-limited in 75–90% of adolescents. Usually, it resolves spontaneously within 1 to 3 years as pubertal progression increases testosterone levels and causes regression of breast tissue. By age 17, only 10% of adolescent males have persistent gynecomastia.
The optical lens has been playing a critical role in almost all areas of science and technology since its invention about 3000 years ago. With the advances in micro- and nanofabrication techniques, continued miniaturization of the conventional optical lenses has always been requested for various applications such as communications, sensors, data storage and a wide range of other technology-driven and consumer-driven industries. Specifically, ever smaller sizes, as well as thinner thicknesses of micro lenses, are highly needed for subwavelength optics or nano-optics with extremely small structures, particularly for visible and near-IR applications. Also, as the distance scale for optical communications shrinks, the required feature sizes of micro lenses are rapidly pushed down. Recently, the excellent properties of newly discovered graphene oxide provide novel solutions to overcome the challenges of current planar focusing devices. Specifically, giant refractive index modification (as large as 10^-1), which is one order of magnitude larger than the current materials, between graphene oxide (GO) and reduced graphene oxide (rGO) have been demonstrated by dynamically manipulating its oxygen content using the direct laser writing (DLW) method. As a result, the overall lens thickness can be potentially reduced by more than ten times. Also, the linear optical absorption of GO is found to increase as the reduction of GO deepens, which results in transmission contrast between GO and rGO and therefore provides an amplitude modulation mechanism.
== Investors == In November 2012, Intarcia received $210M in preferred stock and debt financing from, The Baupost Group, Farallon Capital Management, New Enterprise Associates, New Leaf Venture Partners and Venrock Associates. Other Investors include Greenspring Associates, Alta Partners and Granite Venture Partners. In April 2014, Intarcia secured an additional $200M in financing. RA Capital led the round and was joined by new and existing investors. In April 2015, the company raised $225M in exchange for 1.5% of future global net sales of ITCA 650. In May 2016, Intarcia secured an additional $75M in financing to scale-up manufacturing and inventory in anticipation of ITCA 650s global launch. In September 2016, Intarcia raised an additional $215M in equity financing to prepare for the commercial launch of ITCA 650 in late 2017 and additional pipeline programs.
The Fascist regime in Italy put an end to the social unrest, banning trade unions and jailing socialist leaders, notably Antonio Gramsci. On the other hand, Benito Mussolini largely subsidised the automotive industry, in order to provide vehicles to the army. Turin was a target of Allied strategic bombing during World War II, being heavily damaged by the air raids in its industrial areas as well as in the city centre. Along with Milan, Genoa, and La Spezia, Turin was one of Italy's four cities that suffered area bombing by the RAF; the heaviest raid took place on 13 July 1943, when 295 bombers dropped 763 tons of bombs, killing 792 people. Overall, these raids killed 2,069 inhabitants of Turin, and destroyed or damaged 54% of all buildings in the city. In March 1943 the city's factories were the starting point of the first mass strikes in Fascist Italy. The Allies' campaign in Italy started from the south and slowly moved northwards in the following two years. The northern regions were occupied by Germans and collaborationist forces for several years. Turin was not captured by the Allies until the end of the Spring Offensive of 1945. By the time the vanguard of the armoured reconnaissance units of the Brazilian Expeditionary Force reached the city, it was already freed by the Italian Partisans. They had begun revolting against the Germans and the Italian RSI troops on 25 April 1945. Days later, troops from the US Army's 1st Armored and 92nd Infantry Divisions came to substitute for the Brazilians. In the postwar years, Turin was rapidly rebuilt.
Sources: en.wikipedia.org
Research into automated cell counting began in the early 20th century. A method developed in 1928 used the amount of light transmitted through a diluted blood sample, as measured by photometry, to estimate the red blood cell count, but this proved inaccurate for samples with abnormal red blood cells. Other unsuccessful attempts, in the 1930s and 1940s, involved photoelectric detectors attached to microscopes, which would count cells as they were scanned. In the late 1940s, Wallace H. Coulter, motivated by a need for better red blood cell counting methods following the bombing of Hiroshima and Nagasaki, attempted to improve on photoelectric cell counting techniques. His research was aided by his brother, Joseph R. Coulter, in a basement laboratory in Chicago. Their results using photoelectric methods were disappointing, and in 1948, after reading a paper relating the conductivity of blood to its red blood cell concentration, Wallace devised the Coulter principle—the theory that a cell suspended in a conductive medium generates a drop in current proportional to its size as it passes through an aperture. That October, Wallace built a counter to demonstrate the principle. Owing to financial constraints, the aperture was made by burning a hole through a piece of cellophane from a cigarette package. Wallace filed a patent for the technique in 1949, and in 1951 applied to the Office of Naval Research to fund the development of the Coulter counter.
=== Protecting groups === As a class, esters serve as protecting groups for carboxylic acids. Protecting a carboxylic acid is useful in peptide synthesis, to prevent self-reactions of the bifunctional amino acids. Methyl and ethyl esters are commonly available for many amino acids; the t-butyl ester tends to be more expensive. However, t-butyl esters are particularly useful because, under strongly acidic conditions, the t-butyl esters undergo elimination to give the carboxylic acid and isobutylene, simplifying work-up.
=== 3D printing === In 2017, scientists from Chalmers University of Technology in Sweden demonstrated cartilage tissue engineering using 3D bioprinting. They used two different bioinks with nanofibrillated cellulose (NFC) to conduct the tests: NFC with alginate (NFC/A) and hyaluronic acid (NFC/HA). The bioinks were co-printed with irradiated human chondrocytes [8]. The team had success with NFC/A. In September 2021, researchers created cartilage repair implants utilizing a process of three-dimensional weaving to combine artificial materials with stem cells. The bioartificial implants are designed to partly dissolve over time, leaving only natural tissues in the repaired joints. As of October 2021, scientists have seen success in treating dogs but further research is required before the technique could move to clinical trials for humans. Also in September 2021, scientists from the Nakayama Lab at Saga University and Kyoto University in Japan fabricated 3D printed cartilage constructs from stem cells.
Sources: en.wikipedia.org
It acts on the growth hormone-releasing hormone receptor found on pituitary somatotroph cells. Activation of that receptor triggers growth hormone release through a cyclic AMP dependent pathway.
It links the peptide to serum albumin after administration, which delays removal from circulation. Reported half-life shifts from roughly half an hour to several days as a result.
Most published work tracks serum growth hormone and insulin-like growth factor 1 over time. Sampling schedules and assay methods vary enough that figures are not directly comparable across reports.
No. It is a laboratory-synthesized analog built on a fragment of the natural hormone. The natural peptide is shorter-lived and lacks the stabilizing substitutions found in the synthetic version.