Examorelin (

INN Inns are generally establishments or buildings where travelers can seek lodging, and usually, food and drink. Inns are typically located in the country or along a highway; before the advent of motorized transportation they also provided accommo ...

) (developmental code names EP-23905, MF-6003), also known as hexarelin, is a potent,

synthetic Synthetic things are composed of multiple parts, often with the implication that they are artificial. In particular, 'synthetic' may refer to: Science * Synthetic chemical or compound, produced by the process of chemical synthesis * Synthetic o ...

, peptidic, orally-active, centrally-penetrant, and highly selective

agonist An agonist is a chemical that activates a receptor to produce a biological response. Receptors are cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an antagonist blocks the action of the ago ...

of the ghrelin/growth hormone secretagogue receptor (GHSR) and a

growth hormone secretagogue Growth hormone secretagogues or GH secretagogues (GHSs) are a class of drugs which act as secretagogues (i.e., induce the secretion) of growth hormone (GH). They include agonists of the ghrelin/growth hormone secretagogue receptor (GHSR), such ...

which was developed by Mediolanum Farmaceutici. It is a

hexapeptide Peptides (, ) are short chains of amino acids linked by peptide bonds. Long chains of amino acids are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides. A p ...

with the amino acid sequence His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH₂ which was derived from

GHRP-6 Growth hormone-releasing peptide 6 (GHRP-6) (developmental code name SKF-110679), also known as growth hormone-releasing hexapeptide, is one of several synthetic met-enkephalin analogues that include unnatural D-amino acids, were developed for ...

. These GH-releasing peptides have no sequence similarity to ghrelin, but mimic ghrelin by acting as agonists at the

ghrelin Ghrelin (; or lenomorelin, INN) is a hormone produced by enteroendocrine cells of the gastrointestinal tract, especially the stomach, and is often called a "hunger hormone" because it increases the drive to eat. Blood levels of ghrelin are highe ...

receptor. Examorelin substantially and dose-dependently increases

plasma Plasma or plasm may refer to: Science * Plasma (physics), one of the four fundamental states of matter * Plasma (mineral), a green translucent silica mineral * Quark–gluon plasma, a state of matter in quantum chromodynamics Biology * Blood pla ...

levels of

growth hormone Growth hormone (GH) or somatotropin, also known as human growth hormone (hGH or HGH) in its human form, is a peptide hormone that stimulates growth, cell reproduction, and cell regeneration in humans and other animals. It is thus important in h ...

(GH) in animals and humans. In addition, similarly to

pralmorelin Pralmorelin (INN) (brand name GHRP Kaken 100; former developmental code names KP-102, GPA-748, WAY-GPA-748), also known as pralmorelin hydrochloride (JAN) and pralmorelin dihydrochloride (USAN), as well as, notably, growth hormone-releasing peptid ...

(GHRP-2) and GHRP-6, it slightly and dose-dependently stimulates the release of

prolactin Prolactin (PRL), also known as lactotropin, is a protein best known for its role in enabling mammals to produce milk. It is influential in over 300 separate processes in various vertebrates, including humans. Prolactin is secreted from the pit ...

, adrenocorticotropic hormone (ACTH), and

cortisol Cortisol is a steroid hormone, in the glucocorticoid class of hormones. When used as a medication, it is known as hydrocortisone. It is produced in many animals, mainly by the ''zona fasciculata'' of the adrenal cortex in the adrenal gland ...

in humans. There are conflicting reports on the ability of examorelin to elevate

insulin-like growth factor 1 Insulin-like growth factor 1 (IGF-1), also called somatomedin C, is a hormone similar in molecular structure to insulin which plays an important role in childhood growth, and has anabolic effects in adults. IGF-1 is a protein that in humans is ...

(IGF-1) and

insulin-like growth factor-binding protein 1 Insulin-like growth factor-binding protein 1 (IBP-1) also known as placental protein 12 (PP12) is a protein that in humans is encoded by the ''IGFBP1'' gene. Function This gene is a member of the Insulin-like growth factor-binding protein (IGFB ...

(IGFBP-1) levels in humans, with some studies finding no increase and others finding a slight yet statistically significant increase. Examorelin does not affect plasma levels of

glucose Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using ...

, luteinizing hormone (LH),

follicle-stimulating hormone Follicle-stimulating hormone (FSH) is a gonadotropin, a glycoprotein polypeptide hormone. FSH is synthesized and secreted by the gonadotropic cells of the anterior pituitary gland and regulates the development, growth, pubertal maturation, an ...

(FSH), or

thyroid-stimulating hormone Thyroid-stimulating hormone (also known as thyrotropin, thyrotropic hormone, or abbreviated TSH) is a pituitary hormone that stimulates the thyroid gland to produce thyroxine (T4), and then triiodothyronine (T3) which stimulates the metabolism of ...

(TSH) in humans. Examorelin releases more GH than does

growth hormone-releasing hormone Growth may refer to: Biology * Auxology, the study of all aspects of human physical growth * Bacterial growth * Cell growth * Growth hormone, a peptide hormone that stimulates growth * Human development (biology) * Plant growth * Secondary growth ...

(GHRH) in humans, and produces synergistic effects on GH release in combination with GHRH, resulting in "massive" increases in plasma GH levels even with only low doses of examorelin. Pre-administration of GH blunts the GH-releasing effect of examorelin, while, in contrast, fully abolishing the effect of GHRH. Pre-treatment with IGF-1 also blunts the GH-elevating effect of examorelin.

Testosterone Testosterone is the primary sex hormone and anabolic steroid in males. In humans, testosterone plays a key role in the development of Male reproductive system, male reproductive tissues such as testes and prostate, as well as promoting secondar ...

testosterone enanthate Testosterone enanthate, sold under the brand names Delatestryl and Xyosted among others, is an androgen and anabolic steroid (AAS) medication which is used mainly in the treatment of low testosterone levels in men. It is also used in hormone th ...

, and ethinylestradiol, though not oxandrolone, have been found to significantly potentiate the GH-releasing effects of examorelin in humans. In accordance, likely due to increases in

sex steroid Sex hormones, also known as sex steroids, gonadocorticoids and gonadal steroids, are steroid hormones that interact with vertebrate steroid hormone receptors. The sex hormones include the androgens, estrogens, and progestogens. Their effects are ...

levels,

puberty Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction. It is initiated by hormonal signals from the brain to the gonads: the ovaries in a girl, the testes in a boy. ...

has also been found to significantly augment the GH-elevating actions of examorelin in humans. A partial and reversible tolerance to the GH-releasing effects of examorelin occurs in humans with long-term administration (50–75% decrease in efficacy over the course of weeks to months). Examorelin reached

phase II Phase II, Phase 2 or Phase Two may refer to: Media * Marvel Cinematic Universe: Phase Two, six American superhero films from 2013–2015 * ''Star Trek: Phase II'', an unrealized television series based on the characters of Gene Roddenberry's ''S ...

clinical trial Clinical trials are prospective biomedical or behavioral research studies on human participants designed to answer specific questions about biomedical or behavioral interventions, including new treatments (such as novel vaccines, drugs, dietar ...

s for the treatment of

growth hormone deficiency Growth hormone deficiency (GHD), or human growth hormone deficiency, is a medical condition resulting from not enough growth hormone (GH). Generally the most noticeable symptom is that an individual attains a short height. Newborns may also presen ...

and

congestive heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, a ...

but did not complete development and was never marketed.

References

{{GH/IGF-1 axis signaling modulators Experimental drugs Ghrelin receptor agonists Growth hormone secretagogues Hexapeptides World Anti-Doping Agency prohibited substances

See also

References