If you have been reading about DAC and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-01-21. Where a claim depends on a specific study, the study is described rather than over-claimed.
Clearance profiles diverge sharply between the two versions. The albumin-binding molecule stays in plasma for several days, whereas the unmodified analog is largely gone within about half an hour in reported work. Cleavage by dipeptidyl peptidase IV is a major contributor to the short life of the unmodified sequence. These gaps mean the two versions cannot be substituted for each other in study design or in reading results side by side.
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.
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.
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.
| 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 |
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.
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.
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.
Colony-forming unit-fibroblast Mesenchymal stem cell / marrow stromal cell Chondrocyte Hypertrophic chondrocyte Mesenchymal (mesoderm origin) stem cells are undifferentiated, meaning they can differentiate into a variety of generative cells commonly known as osteochondrogenic (or osteogenic, chondrogenic, osteoprogenitor, etc.) cells. When referring to bone, or in this case cartilage, the originally undifferentiated mesenchymal stem cells lose their pluripotency, proliferate and crowd together in a dense aggregate of chondrogenic cells (cartilage) at the location of chondrification. These chondrogenic cells differentiate into so-called chondroblasts, which then synthesize the cartilage extracellular matrix (ECM), consisting of a ground substance (proteoglycans, glycosaminoglycans for low osmotic potential) and fibers. The chondroblast is now a mature chondrocyte that is usually inactive but can still secrete and degrade the matrix, depending on conditions. Cell culture studies of excess Vitamin B inhibits the synthesis of chondroitin sulfate by chondrocytes and causes the inhibition of chondrogenesis in the developing embryo which may result in limb malformations. Chondrocytes undergo terminal differentiation when they become hypertrophic, which happens during endochondral ossification. This last stage is characterized by major phenotypic changes in the cell.
A lower-end product includes salt, hydrogenated fat, monosodium glutamate, flavor enhancers, and flavors. It is labelled as "beef flavor" without beef. A mid-end product typically combines cheaper sources of flavor with actual meat/bone/vegetable (usually first cooked into an extract) and/or animal fat. For example, Maggi bouillon cubes are manufactured from iodized salt, hydrogenated palm oil, wheat flour, flavor enhancers (monosodium glutamate, disodium inosinate, disodium guanylate), chicken fat, chicken meat, sugar, caramel, yeast extract, onion, spices (turmeric, white pepper, coriander), and parsley. A high-end product typically mainly rely on meat/bone/vegetable (usually extracted) for the meaty flavor and savoriness, such as described in a 2004 patent. As an example, "Better than Bouillion" is made from roasted chicken, salt, sugar, maltodextrin, chicken stock, yeast extract, onion powder, garlic powder, tumeric, and flavoring.
=== Video games === Half-Life (1998) Half-Life 2 (2004) Half-Life 2: Episode One (2006) Half-Life 2: Episode Two (2007) Portal (2007) Counter-Strike: Global Offensive (additional music, 2015) Vanishing Realms: Rite of Steel (2016-2019)
Sources: en.wikipedia.org
In November 1942, the Japanese built an airfield on Engebi Island. As they used it only for refueling planes between Truk and islands to the east, no aviation personnel were stationed there, and the island had only token defenses. When the Gilberts fell to the United States, the Imperial Japanese Army assigned defense of the atoll to the 1st Amphibious Brigade, formed from the 3rd Independent Garrison, which had previously been stationed in Manchukuo. The 1st Amphibious Brigade arrived on January 4, 1944. Some 2,586 of its 3,940 men were left to defend Eniwetok Atoll, supplemented by aviation personnel, civilian employees, and laborers. However, they were unable to finish the fortifications before the American attack came in February. During the ensuing Battle of Eniwetok, the Americans captured Enewetak in a five-day amphibious operation. Fighting mainly took place on Engebi Islet, site of the most important Japanese installation, although some combat occurred on the main islet of Enewetak itself and on Parry Island, where there was a Japanese seaplane base. Following its capture, the anchorage at Enewetok became a major US Naval Advance Base with Service Squadron 4 and Service Squadron 10 stationed in the lagoon. The daily average of ships present during the first half of July 1944 was 488; during the second half of July, the daily average number of ships at Enewetak was 283. Naval Base Eniwetok was part of the vast Naval Base Marshall Islands. US Navy Seabees of the 110th Naval Construction Battalion arrived on February 21 and 27 to begin construction of Stickell Field.
== How it works == The LIT uses a set of quadrupole rods to confine ions radially and a static electrical potential on the end electrodes to confine the ions axially. The LIT can be used as a mass filter or as a trap by creating a potential well for the ions along the axis of the trap. The mass of trapped ions may be determined if the m/z lies between defined parameters. Advantages of the LIT design are high ion storage capacity, high scan rate, and simplicity of construction. Although quadrupole rod alignment is critical, adding a quality control constraint to their production, this constraint is additionally present in the machining requirements of the 3D trap.
== Recognition == In 2003, a GameSpy editorial cited Minh Le as the most important reason Half-Life was still popular five years after it was released. IGN ranked Jess Cliffe and Minh Le as number 14 in their "Top 100 Game Creators of All Time" list.
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 synthetic analogue modeled on the first 29 residues of human GHRH. The substitutions and any linker are laboratory modifications rather than features of the endogenous peptide.