If you have been reading about half-life 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.
Updated 2025-12-18. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Peptide class | Synthetic GHRH analogue | Built on a 29 residue sequence |
| Primary target | GHRH receptor (GHRHR) | Class B G protein coupled receptor |
| Unconjugated half life | Minutes | Limited by protease degradation |
| Key modification | Four residue substitutions | Positions 2, 8, 15 and 27 |
| Common synonym | Modified GRF(1-29) | Usually denotes the form without DAC |
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.
The attached maleimide group explains the unusual duration of the DAC version. After injection it reacts with the thiol of cysteine-34 on serum albumin, forming a stable covalent bond. The resulting conjugate is too large for rapid kidney filtration and is shielded from many peptidases. Reported half-lives for this form reach several days, whereas the version without the group is cleared in roughly half an hour. That gap is the main pharmacological difference between the two.
The albumin-binding version stays in circulation for days, because covalent attachment to serum albumin shields the peptide from rapid filtration and degradation. Reported half-lives for this form fall in the range of several days. The version without the linker is cleared in minutes, with estimates often near thirty minutes in animal work. These figures come from small studies and vary with assay method, species, and route, so they are best read as approximate rather than fixed constants.
Studies in this area generally track growth hormone pulses, insulin-like growth factor 1 concentrations, and occasionally body composition endpoints. Most published human data come from early, small trials, and questions about long-term effects remain open. Whether repeated exposure alters pituitary responsiveness over time is not settled. Analytical work relies on immunoassays for the hormones and on mass spectrometry for the peptide itself, because the two measurements answer different questions.
Whereas the Principal Allied Powers have also agreed that the Mandatory should be responsible for putting into effect the declaration originally made on November 2nd, 1917, by the Government of His Britannic Majesty, and adopted by the said Powers, in favor of the establishment in Palestine of a national home for the Jewish people, it being clearly understood that nothing should be done which might prejudice the civil and religious rights of existing non-Jewish communities in Palestine, or the rights and political status enjoyed by Jews in any other country.... A statement on "British Policy in Palestine," issued on 3 June 1922 by the Colonial Office, placed a restrictive construction upon the Balfour Declaration. The statement excluded "the disappearance or subordination of the Arabic population, language or customs in Palestine" or "the imposition of Jewish nationality upon the inhabitants of Palestine as a whole", and made it clear that in the eyes of the mandatory Power, the Jewish National Home was to be founded in Palestine and not that Palestine as a whole was to be converted into a Jewish National Home. The Committee noted that the construction, which restricted considerably the scope of the National Home, was made prior to the confirmation of the Mandate by the Council of the League of Nations and was formally accepted at the time by the Executive of the Zionist Organization. The Partition Resolution of the UN General Assembly died at birth when rejected by the Arabs. The UNGA has only the power to recommend.
MRI has the advantages of having very high spatial resolution and is very adept at morphological imaging and functional imaging. MRI does have several disadvantages though. First, MRI has a sensitivity of around 10−3 mol/L to 10−5 mol/L, which, compared to other types of imaging, can be very limiting. This problem stems from the fact that the population difference between the nuclear spin states is very small at room temperature. For example, at 1.5 teslas, a typical field strength for clinical MRI, the difference between high and low energy states is approximately 9 molecules per 2 million. Improvements to increase MR sensitivity include increasing magnetic field strength and hyperpolarization via optical pumping or dynamic nuclear polarization. There are also a variety of signal amplification schemes based on chemical exchange that increase sensitivity. To achieve molecular imaging of disease biomarkers using MRI, targeted MRI contrast agents with high specificity and high relaxivity (sensitivity) are required. To date, many studies have been devoted to developing targeted-MRI contrast agents to achieve molecular imaging by MRI. Commonly, peptides, antibodies, or small ligands, and small protein domains, such as HER-2 affibodies, have been applied to achieve targeting. To enhance the sensitivity of the contrast agents, these targeting moieties are usually linked to high payload MRI contrast agents or MRI contrast agents with high relaxivities.
The international community refused to accept the validity of any agreement which did not incorporate the main nationalist parties. The British government (then led by the recently elected Margaret Thatcher) issued invitations to all parties to attend a peace conference at Lancaster House. These negotiations took place in London in late 1979. The three-month-long conference almost failed to reach conclusion, due to disagreements on land reform, but resulted in the Lancaster House Agreement. UDI ended, and Rhodesia temporarily reverted to the status of a British colony (the 'Colony of Southern Rhodesia'). As per the agreement, Lord Soames became governor with full legislative and executive powers. The Lancaster House Agreement further provided for a ceasefire which was followed by an internationally supervised general election, held in February 1980. ZANU led by Robert Mugabe won this election, some alleged, by terrorising its political opposition, including supporters of ZAPU, through former insurgents that had not confined themselves to the designated guerrilla assembly points, as stipulated by the Lancaster House Agreement. The observers and Soames were accused of looking the other way, and Mugabe's victory was certified. Nevertheless, few could doubt that Mugabe's support within his majority Shona tribal group was extremely strong. The Rhodesian military seriously considered mounting a coup against a perceived stolen election ("Operation Quartz") to prevent ZANU from taking over the country.
== Staudinger ligation == The Staudinger ligation is a reaction developed by the Bertozzi group in 2000 that is based on the classic Staudinger reaction of azides with triarylphosphines. It launched the field of bioorthogonal chemistry as the first reaction with completely abiotic functional groups although it is no longer as widely used. The Staudinger ligation has been used in both live cells and live mice.
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Detergents, such as SDS or Tween-20, which are used to break open cells and release the DNA. Protease enzymes, such as Proteinase K, which are used to digest proteins that may be binding to the DNA. Phenol and chloroform, which are used to separate the DNA from other cellular components. Ethanol or isopropanol, which are used to precipitate the DNA. Salt, such as NaCl, which is often used to help dissolve the DNA and maintain its stability. EDTA, which inactivates enzymes such as nucleases by chelating (binding) metals ions needed as cofactors. Tris-HCL, which is used to maintain the pH at the optimal condition for DNA extraction.
Practical Physiology (1903) Recent Advances in Physiology (with Leonard E. Hill, 1905) Diabetes: its Pathological Physiology (1913) Physiology for dental students (with R. G. Pearce, 1915) Physiology and Biochemistry in Modern Medicine (1st edition 1918) Insulin and its Use in Diabetes (with W. R. Campbell, 1925) Carbohydrate Metabolism and Insulin (1926) The Fuel of life: Experimental Studies in Normal and Diabetic Animals (1928) Macleod, J.J.R., "Gluconeogenesis and the Energy Material of Muscle", The Australian Journal of Experimental Biology and Medical Science, Vol.9, No.1, (January 1932), pp. 119-125.
The 1982 biopic film Frances depicts actress Frances Farmer (the subject of the film) undergoing transorbital lobotomy (though the idea that a lobotomy was performed on Farmer, and that Freeman performed it, has been criticized as having little or no factual foundation). Katherine Dunn's 1989 novel Geek Love centers on a freak show whose leader founds a cult practicing amputation and lobotomy. Joyce Carol Oates's 1995 novel Zombie includes a verbatim extract of Freeman and Watts's 1942 treatise Psychosurgery describing leucotomy. The antihero Quentin reads this passage and similar descriptions of lobotomy. Sexually fantasizing about submissive lobotomized patients, Quentin seeks seeks to replicate Freeman's transorbital lobotomy technique on his victims using an icepick. Jeffrey Dahmer was Oates's inspiration for the character of Quentin; Dahmer did not use Freeman's technique on his victims, but rather drilled into their skulls to pour acid into them.
Surgery to remove the prostate is called prostatectomy, and is usually done as a treatment for cancer limited to the prostate, or for prostatic enlargement. When it is done, it may be done as open surgery or as laparoscopic (keyhole) surgery. These are done under general anaesthetic. Usually the procedure for cancer is a radical prostatectomy, which means that the seminal vesicles are removed and the vasa deferentia are also tied off. Part of the prostate can also be removed from within the urethra, called transurethral resection of the prostate (TURP). Open surgery may involve a cut that is made in the perineum, or via an approach that involves a cut down the midline from the belly button to the pubic bone. Open surgery may be preferred if there is a suspicion that lymph nodes are involved and they need to be removed or biopsied during a procedure. A perineal approach will not involve lymph node removal and may result in less pain and a faster recovery following an operation. A TURP procedure uses a tube inserted into the urethra via the penis and some form of heat, electricity or laser to remove prostate tissue. The whole prostate can be removed. Complications that might develop because of surgery include urinary incontinence and erectile dysfunction because of damage to nerves during the operation, particularly if a cancer is very close to nerves. Ejaculation of semen will not occur during orgasm if the vasa deferentia are tied off and seminal vesicles removed, such as during a radical prosatectomy. This will mean a man becomes infertile.
As an AAS, stanozolol is an agonist of the androgen receptor (AR), similarly to androgens like testosterone and DHT. Its affinity for the androgen receptor is about 22% of that of dihydrotestosterone. Stanozolol is not a substrate for 5α-reductase as it is already 5α-reduced, and so is not potentiated in so-called "androgenic" tissues like the skin, hair follicles, and prostate gland. This results in a greater ratio of anabolic to androgenic activity compared to testosterone. In addition, due to its 5α-reduced nature, stanozolol is non-aromatizable, and hence has no propensity for producing estrogenic effects such as gynecomastia or fluid retention. Stanozolol also does not possess any progestogenic activity of significance. Because of the presence of its 17α-methyl group, the metabolism of stanozolol is sterically hindered, resulting in it being orally active, although also hepatotoxic.
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4 March The Rector of Saigon University, Professor Tran Anh, was shot by VC on a motorcycle; previously he had been notified that he was on the "death list" of the "Suicide Regiment of the Saigon Youth Guard."
AMPylators have been shown to be comparable to kinases due to their ATP hydrolysis activity and reversible transfer of the metabolite to a hydroxyl side chain of the protein substrate. However, AMPylation catalyse a nucleophilic attack on the α-phosphate group, while kinase in the phosphorylation reaction targets γ-phosphate. The nucleophilic attack of AMPylation leads to release Pyrophosphate and the AMP-modified protein are the products of the AMPylation reaction.
It sublimes, is volatile with steam, and is soluble in most organic solvents as well as aqueous alkaline solutions. DNP can be produced by hydrolysis of 2,4-dinitrochlorobenzene. Other routes of DNP synthesis include nitration of monochlorobenzene, nitration of benzene with nitrogen dioxide and mercurous nitrate, oxidation of 1,3-dinitrobenzene, and nitration of phenol with nitric acid. Nitration of phenol is not practical commercially because partial decomposition of the phenolic ring occurs. A dust explosion is possible with DNP in powder or granular form in the presence of air. DNP may explosively decompose when submitted to shock, friction or concussion, and may explode upon heating. DNP forms explosive salts with strong bases as well as ammonia, and emits toxic fumes of nitrogen dioxide when heated to decomposition.
26 December Sid Ashton, accountant, chief executive of Te Rūnanga o Ngāi Tahu (1993–2002), chair of the Charities Commission (2005–2011) (born 1936). Ken Thompson, police officer, Commissioner of Police (1983–1987) (born 1932). 27 December Dave Leathwick, parasitologist (AgResearch) (born 1955). Garrick Tremain, cartoonist (Otago Daily Times) and painter (born 1941).
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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.
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.
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.
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.