The short version of somatotroph fits in a sentence. The long version — which is the one that helps — is below.
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Compared with other secretagogues such as GHRP-2, GHRP-6, and hexarelin, ipamorelin is described as more selective. Published animal work reports little or no increase in adrenocorticotropic hormone, cortisol, or prolactin at doses that release growth hormone. This selectivity is the property most often cited in the research literature. Whether the same profile holds across species and dosing schedules remains an open question, since human data are limited and come largely from small studies.
Ipamorelin is a synthetic pentapeptide that belongs to the growth hormone secretagogue family. Its sequence is Aib-His-D-2-Nal-D-Phe-Lys-NH2, and its molecular mass is approximately 711.9 daltons. The compound was described in the late 1990s by researchers seeking molecules that release growth hormone with fewer side effects than earlier secretagogues. It is a laboratory and research compound, not an approved medicine in most jurisdictions.
At the molecular level, ipamorelin acts as an agonist at the growth hormone secretagogue receptor, also called the ghrelin receptor or GHS-R1a. Binding to this receptor on pituitary somatotroph cells triggers a signaling cascade that leads to growth hormone release. The effect is mediated through phospholipase C and calcium mobilization rather than through the cyclic AMP pathway used by growth hormone releasing hormone. The two pathways are complementary, and combined stimulation produces a larger response than either alone.
In animal and early human studies, ipamorelin produces pulsatile growth hormone release and a secondary rise in insulin-like growth factor 1. The magnitude and duration of that rise depend on route, sampling schedule, and the baseline endocrine state of the subject. Whether repeated exposure alters the response over time is not firmly settled, since some reports describe stable pulsatility while others note attenuation. Most published data come from small samples, which limits the strength of any general claim about long-term behavior.
Ipamorelin is a synthetic pentapeptide that belongs to the growth hormone secretagogue class of compounds. Its sequence is Aib-His-D-2-Nal-D-Phe-Lys-NH2, a structure that differs from natural ghrelin in length and in the presence of non-natural amino acid residues. Early laboratory work described it as a comparatively selective agent that stimulates growth hormone release with limited effect on other pituitary hormones. The compound is supplied as a lyophilized solid for research use and has no identified natural source in the body.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic pentapeptide | Growth hormone secretagogue family |
| Molecular mass | Approximately 711.9 Da | Free base, calculated value |
| Receptor target | GHS-R1a, the ghrelin receptor | Agonist activity reported |
| Sequence | Aib-His-D-2-Nal-D-Phe-Lys-NH2 | C-terminal amide |
| Reported selectivity | Little change in ACTH, cortisol, prolactin | Based mainly on animal data |
Ipamorelin is a synthetic pentapeptide that belongs to the growth hormone secretagogue class. It acts as an agonist at the ghrelin receptor, also called the growth hormone secretagogue receptor type 1a. The compound was designed in the 1990s during a search for agents that release growth hormone with fewer off-target hormonal effects than earlier secretagogues. It appears in the research literature under several sequence-based names. Material supplied for laboratory work is normally a lyophilized solid, and it is not marketed as an approved therapeutic in major jurisdictions.
The molecule contains five residues, including alpha-aminoisobutyric acid, D-2-naphthylalanine, and D-phenylalanine, and it ends in a lysine amide. Non-natural and D-configured residues make the chain less susceptible to common peptidases, which helps explain its resistance to rapid breakdown. Its molecular formula is C38H49N9O5, corresponding to a free-base mass near 711.9 daltons. The C-terminal amide removes a negative charge and is a recurring feature in receptor-active peptides of this family. These structural choices are usually discussed as the basis for its selectivity profile.
Published animal and early human work describes growth hormone release that is separated from comparable rises in adrenocorticotropic hormone and cortisol. Prolactin changes are reported as small in the same studies. Selectivity is attributed to binding at the ghrelin receptor and to the downstream signaling that follows, rather than to differences in how quickly the peptide is cleared. Authors commonly label the compound selective rather than potent, because the same mass produces a smaller growth hormone response than some older secretagogues tested in parallel. Whether that profile holds across species and routes of administration remains an open question.
At the receptor level, ipamorelin binds GHS-R1a and triggers signaling through Gq-coupled pathways. Activation leads to calcium release and downstream effects in pituitary somatotroph cells. These events promote the release of growth hormone into circulation. The response depends on the presence of the receptor and on the physiological state of the animal or tissue studied. Because the receptor is also found in other tissues, effects beyond the pituitary have been examined in laboratory models, though the extent of those effects remains an area of ongoing study.
One distinguishing feature reported in animal studies is selectivity. Ipamorelin stimulated growth hormone release with limited elevation of adrenocorticotropic hormone or cortisol compared with earlier secretagogues such as GHRP-6. This pattern has been described as more selective for the growth hormone axis. The finding comes mainly from preclinical work, and the degree to which it holds across species and doses is not fully settled. Reports also describe effects on gastric motility in animal models, suggesting activity outside the pituitary, though the clinical relevance of this observation is uncertain.
Ipamorelin is a synthetic pentapeptide that acts on the growth hormone secretagogue receptor, also known as the ghrelin receptor. Its sequence contains five amino acid residues, including a non-natural residue that increases stability against enzymatic breakdown. The compound was developed in the 1990s as part of research into small peptides that stimulate pituitary hormone release. Unlike larger protein hormones, it can be produced by solid-phase peptide synthesis and characterized by standard analytical methods.
In adults and children with bipolar disorder, SSRIs may cause a bipolar switch from depression into hypomania/mania, mixed states, or rapid cycling. When taken with mood stabilizers, the risk of switching is not increased; however, when taking SSRIs as a monotherapy, the risk of switching may be twice or three times that of the average. The changes are not often easy to detect and require monitoring by family and mental health professionals. This switch might happen even with no prior (hypo)manic episodes and might therefore not be foreseen by the psychiatrist. In addition to causing a switch from depression to mania, antidepressants may also cause rapid switches between mood states, known as rapid cycling. Some types of antidepressants are more likely to cause a manic switch or rapid cycling. Serotonin-norepinephrine reuptake inhibitors such as venlafaxine or duloxetine, tetracyclic antidepressants such as mirtazapine, or older tricyclic antidepressants are more likely than SSRIs or bupropion to cause manic switches or rapid cycling. Atypical antipsychotics are approved for bipolar depression. The FDA has approved lurasidone, quetiapine, olanzapine/fluoxetine combination, cariprazine, and lumateperone for bipolar depression.
== January 18, 1982 (Monday) == A simultaneous crash of four T-38 jets killed the four pilots for the Thunderbirds stunt flying team of the U.S. Air Force, as they were flying in formation at Indian Springs Air Force Auxiliary Field in Nevada in preparation of a flying show set for March. U.S. Army Lieutenant Colonel Charles R. Ray, an assistant military attache in France, was shot and killed, in front of his home in Paris as he was leaving his apartment to drive to his job at the U.S. Embassy. Georges Ibrahim Abdallah, a terrorist from Lebanon who had founded the Lebanese Armed Revolutionary Factions, would be arrested almost three years later in Lyon, convicted of complicity in the murder of Lt. Col. Ray and of the March 31 killing of Israeli diplomat Yacov Barsimantov, and would serve 41 years of a life sentence before being released in 2025. Born: Joanna Newsom, American folk singer; in Grass Valley, California Phạm Phương Thảo, Vietnamese folk singer; in Nghi Lộc district, Nghệ An province Died: Juan O'Gorman, 76, Mexican artist and architect, was found dead from an apparent suicide. Frank C. Baxter, 85, American literature professor and television host of the CBS series Shakespeare on TV and the ABC series Telephone Time, winner of seven Emmy Awards, including Outstanding Male Performer (1954), and 1960 for Outstanding Male Personality (1960). Josef Mai, 94, German fighter ace with 30 victories in World War One; Trent Lehman, 20, former American child actor known for Nanny and the Professor, hanged himself.
Women consistently presented higher obesity prevalence than men throughout the Vigitel surveillance period. In 2006, obesity affected 12.1% of women and 11.4% of men. By 2024, prevalence had increased to 26.7% among women and 24.4% among men. Both sexes experienced substantial increases in obesity prevalence, although women maintained higher rates throughout the period.
=== Connection with Cancer treatment === hCTR1 is upregulated in various cancer types, and it's associated with prognosis in several solid tumors. Atox1 and ATP7B were found to be important for Pt-based drug resistance. hCTR1 plays a role in oncology, hCTR1 facilitates uptake of platinum-based chemotherapeutic agents, such as cisplatin. Yeast and mammalian cells lacking CTR1 were resistant to cisplatin, while cells overexpressing CTR1 accumulated more of the drug. Tumor cells when exposed to cisplatin often react by increased degradation of hCTR1, thereby they become drug-resistant while simultaneously exhibiting signs of perturbed copper homeostasis. Studies of Atox1 in cancer cells demonstrated that this copper chaperone is crucial for cancer cell proliferation and survival. Small molecules targeting Atox1 have been proved to effectively block Cu-trafficking. For that reason reduce cell proliferation in lung, leukemia, breast, head, and neck cancer cell lines by elevating cellular ROS levels and reducing cellular NADPH and GSH levels. In contrast, healthy cells were barely affected by these small molecules.
=== Commanding officers === 1950 Lt Col Mike Calvert, Royal Engineers 1951 Lt Col John Sloane, Argyll and Sutherland Highlanders 1953 Lt Col Oliver Brooke, Welch Regiment 1954 Lt Col Michael Osborn, West Yorkshire Regiment 1955 Lt Col George Lea, Lancashire Fusiliers and Parachute Regiment 1957 Lt Col Tony Deane-Drummond, Royal Signals 1960 Lt Col Ronald Dare Wilson, Royal Northumberland Fusiliers 1962 Lt Col John Woodhouse, Dorset Regiment and East Surreys 1965 Lt Col Michael Wingate-Gray, Black Watch 1967 Lt Col John Slim, Argyll and Sutherland Highlanders 1969 Lt Col John Watts, Royal Irish Rangers 1972 Lt Col Peter de la Billière, Light Infantry 1974 Lt Col Anthony Jeapes, Devonshire and Dorset Regiment 1977 Lt Col Mike Wilkes, Royal Artillery 1982 Lt Col Mike Rose, Coldstream Guards 1984 Lt Col Andrew Massey, Royal Corps of Transport 1986 Lt Col Cedric Delves, Devonshire and Dorset Regiment 1989 Lt Col John Holmes, Scots Guards n/k Lt Col Jonathan "Jacko" Page, Parachute Regiment 2001 Lt Col Ed Butler, Royal Green Jackets 2002 Lt Col Mark Carleton-Smith, Irish Guards 2007 Lt Col Richard Williams, Parachute Regiment 2012 Lt Col Nick Perry, King's Royal Hussars
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== Animal models == Knockout mice of GPX4 die at embryonic day 8 and conditional inducible deletion in adult mice (neurons) results in degeneration and death in less than a month. Targeted disruption of the mitochondrial GPX4 isoform (mGPX4) caused infertility in male mice and disruption of the nuclear GPX4 isoform (nGPX4) reduced the structural stability of sperm chromatin, yet both knockout mouse models (for mGPX4 and nGPX4) were fully viable. Surprisingly, knockout of GPX4 heterozygously in mice (GPX4+/−) increases their median life span. Knockout studies with GPX1, GPX2, or GPX3 deficient mice showed that cytosolic GPX4 is so far the only glutathione peroxidase that is indispensable for embryonic development and cell survival. As mechanisms to dispose of both hydrogen peroxide and lipid hydroperoxides are essential to life, this indicates that in contrast to the multiple metabolic pathways that can be utilized to dispose of hydrogen peroxide, pathways for the disposal of lipid hydroperoxides are limited. While mammals have only one copy of the GPX4 gene, fish have two copies, GPX4a and GPX4b. The GPX4's appear to play a greater role in the fish GPX system than in mammals. For example, in fish GPX4 activity contributes to a greater extent to total GPX activity, GPX4a is the most highly expressed selenoprotein mRNA (in contrast to mammals where it is GPX1 mRNA) and GPX4a appears to be highly inducible to changes within the cellular environment, such as changes in methylmercury and selenium status.
==== MeSH E05.318.780 – epidemiologic research design ==== MeSH E05.318.780.074 – control groups MeSH E05.318.780.150 – cross-over studies MeSH E05.318.780.300 – double-blind method MeSH E05.318.780.485 – matched-pair analysis MeSH E05.318.780.500 – meta-analysis MeSH E05.318.780.700 – random allocation MeSH E05.318.780.725 – reproducibility of results MeSH E05.318.780.762 – sample size MeSH E05.318.780.800 – sensitivity and specificity MeSH E05.318.780.800.650 – predictive value of tests MeSH E05.318.780.800.750 – roc curve MeSH E05.318.780.850 – single-blind method
=== Acquired resistance === Evolution of microbial resistance to vancomycin is a growing problem, especially in healthcare facilities such as hospitals. While newer alternatives to vancomycin exist, such as linezolid (2000) and daptomycin (2003), the widespread use of vancomycin makes resistance to it a significant worry, especially for individual patients if resistant infections are not quickly identified and the patient continues an ineffective treatment. Vancomycin-resistant Enterococcus emerged in 1986. Vancomycin resistance evolved in more common pathogenic organisms during the 1990s and 2000s, including vancomycin-intermediate S. aureus (VISA) and vancomycin-resistant S. aureus (VRSA). Agricultural use of avoparcin, another similar glycopeptide antibiotic, may have contributed to the evolution of vancomycin-resistant organisms. One mechanism of resistance to vancomycin involves the alteration to the terminal amino acid residues of the NAM/NAG-peptide subunits, under normal conditions, D-alanyl-D-alanine, to which vancomycin binds. The D-alanyl-D-lactate variation results in the loss of one hydrogen-bonding interaction (4, as opposed to 5 for D-alanyl-D-alanine) possible between vancomycin and the peptide. This loss of just one point of interaction results in a 1000-fold decrease in affinity. The D-alanyl-D-serine variation causes a six-fold loss of affinity between vancomycin and the peptide, likely due to steric hindrance. In enterococci, this modification appears to be due to the expression of an enzyme that alters the terminal residue.
=== Overdose === Overdose and intoxication with benzodiazepines, including clobazam, may lead to CNS depression, associated with drowsiness, confusion, and lethargy, possibly progressing to ataxia, respiratory depression, hypotension, and coma or death. The risk of a fatal outcome is increased in cases of combined poisoning with other CNS depressants, including alcohol.
=== Controversies === Alteplase is underused in low- and middle-income countries. This may be due to its high cost and the fact that it is often not covered by health insurance. There may be citation bias in the literature on alteplase in ischemic stroke, as studies reporting positive results for tissue plasminogen activator are more likely to be cited in following studies than those reporting negative or neutral results. There is a sex difference in the use of intravenous tissue plasminogen activator, as it is less likely to be used for women with acute ischemic stroke than men. However, this difference has been improving since 2008.
Sources: en.wikipedia.org
==== Mineral extraction and hardware footprint ==== The physical infrastructure of AI, specifically the Graphics Processing Units (GPUs) and data centres required to train and run large language models, relies heavily on critical minerals and rare earth elements. A 2026 study published in Nature Communications Earth & Environment quantified the material footprint of AI training, revealing that AI hardware consists of approximately 90% heavy metals. The study estimated that training a single large language model requires the equivalent lifetime consumption of between 1,760 and 8,800 GPUs, underscoring that incremental model performance gains come at disproportionately high material costs. The extraction of these minerals, such as cobalt, lithium, tantalum, and coltan, is heavily concentrated in the Global South and is frequently associated with severe environmental degradation and human rights abuses. For example, the Democratic Republic of Congo (DRC) holds roughly 70% of the world's cobalt reserves, alongside vast deposits of coltan and copper. Academic analyses note that the global AI supply chain relies on a familiar geopolitical division of labour: African countries mine the raw materials, while Western and East Asian economies refine them and capture the technological value. In the UK, a coalition of NGOs including Friends of the Earth, the Trade Justice Movement, and the London Mining Network published a joint report in May 2026 criticising the UK Government's critical minerals agenda.
Although some worms have eyes (e.g. leeches, some polychaetes), earthworms do not. However, they do have specialized photosensitive cells called "light cells of Hess". These photoreceptor cells have a central intracellular cavity (phaosome) filled with microvilli. As well as the microvilli, there are several sensory cilia in the which are structurally independent of the microvilli. The photoreceptors are distributed in most parts of the epidermis, but are more concentrated on the back and sides of the worm. A relatively small number occur on the ventral surface of the first segment. They are most numerous in the prostomium, and reduce in density in the first three segments; they are very few in number past the third segment.
This process is run thousands or millions of times. The number of times a single tree is visited during the course of the chain is an approximation of its posterior probability. Some of the most common algorithms used in MCMC methods include the Metropolis–Hastings algorithms, the Metropolis-Coupling MCMC (MC³) and the LOCAL algorithm of Larget and Simon.
== Overview == The aquatic inorganic carbon system is composed of the various ionic, dissolved, solid, and/or gaseous forms of carbon dioxide in water. These species include dissolved carbon dioxide, carbonic acid, bicarbonate anion, carbonate anion, calcium carbonate, magnesium carbonate, and others. The relative amounts of each species in a body of water depends on physical variables including temperature and salinity, as well as chemical variables like pH and gas partial pressure. Variables like alkalinity and dissolved (or total) inorganic carbon further define a mass and charge balance that constrains the total state of the system. Given any two of the four central inorganic carbon system parameters (pH, alkalinity, dissolved inorganic carbon, partial pressure of carbon dioxide) the remainder may be derived by solving a system of equations that adhere to the principles of chemical thermodynamics. For most of the 20th century, chemical equilibria in marine and freshwater systems were calculated according to various conventions, which led to discrepancies among laboratories' calculations and limited scientific reproducibility. Since 1998, a family of software programs called CO2SYS has been widely used. This software calculate chemical equilibria for aquatic inorganic carbon species and parameters. Their core function is to use any two of the four central inorganic carbon system parameters (pH, alkalinity, dissolved inorganic carbon, and partial pressure of carbon dioxide) to calculate various chemical properties of the system.
Sources: en.wikipedia.org
Ipamorelin is a synthetic pentapeptide that stimulates growth hormone release by activating the ghrelin receptor. It is handled as a research tool rather than as a licensed therapeutic product. Its short chain length makes it comparatively simple to synthesize and analyze.
Both bind the same receptor, but ghrelin is a 28-amino-acid hormone with roles in appetite and energy balance. Ipamorelin is a much smaller synthetic peptide selected for growth hormone release with limited effect on appetite signaling in animal models. The full overlap between their effects is not completely mapped.
Most published data come from animal studies and a small number of human trials. Findings on growth hormone release are reasonably consistent, while long-term effects and direct comparisons with other secretagogues remain incompletely studied. Open questions include duration of action across different populations.
It is a synthetic pentapeptide in the growth hormone secretagogue family and acts as an agonist at the ghrelin receptor. It is handled as a laboratory research compound rather than a naturally occurring hormone.