Drug Names: GHRP-2, GHRP-6
GHRP-2 is a drug used to stimulate the pituitary to release growth hormone. Growth hormone releasing peptide-2 and 6 are abbreviated GHRP-2 and GHRP-6. GHRP-6 and GHRP-2 are analogs expressing essentially all shared effects of hexapeptide-type growth hormone secretagogue (GHS). GHRP-2 acts on the same receptor and utilizes the same mechanism as GHRP-6, despite the amino acid composition of the peptides 12. GHRP-2, GHRP-6 are collectively referred to as GHRP.
Uses: Assessment of growth hormone deficiency (GHD) 3
Pharmacologic Category: GHRP-2/ GHRP-6, are members of the growth hormone secretagogue (GHS) drug class.
Other names: GHRP Kaken 100, Pralmorelin
GHRP-2 is mainly used as a diagnostic agent in Japan to assess growth hormone deficiency (GHD) or abnormal growth hormone production. Kaken Pharmaceutical manufacturers this product in a single dose form, to be used clinically for diagnostic purposes 3.
General Information: GHRP-2, a hexapeptide containing six amino acid residues, is one of the most potent members of the GHS drug class 45. It can significantly promote the release of growth hormone (GH), improving the serum concentrations of GH and subsequently insulin-like growth factor 1 (IGF-1) in animals and humans 6789. GHRP-2 is readily degraded after reaching the bloodstream, its biological half-life is approximately 30 min. Peak GH concentration occur at approximately 15 min after administration 69. Due to the biological half-life and bioavailability of GHRP-2, administration must occur periodically several times a day, in multiple subcutaneous-injections 10. GHRP-2 has a dose- and age-dependent stimulatory effect on somatotrope secretion, age is inversely related with growth hormone response. Releasing more growth hormone than does the maximal effective dose of GHRH 11. GHRP-2 has as slight stimulatory effect on prolactin, ACTH and cortisol secretion 11. Most notably, the prolactin -releasing activity of GHRP-2 is apparent 11. GH-releasing effect of GHRP-2 has been demonstrated to be several fold higher than baseline growth hormone levels 121314. As monotherapy GHRP-2 is capable of releasing more GH than the highest effective dose of GHRH 45151617. It has been demonstrated that 1, 3 and 10 mcg/kg SC GHRP-2 administration elicits a dose-related GH response 18. There is an Age-related reduction in the somatotrope responsiveness to GHRP-6, and GHRP-2 as well as to new non-peptidyl GHRPs 1920. New findings strongly suggest that GHRP-2 has significant direct effects on muscle cells (myocytes) in skeletal muscle 21. Two proteins which specifically in muscle tissue and are responsible for the degradation of muscular protein, Atrogin-1 and MuRF1, have been linked to a diverse range of conditions that are characterized by muscle atrophy [24-26]. GHRP-2 acts through the growth hormone secretagogue receptor (GHSR1a) to suppress the expression of these muscle degrading proteins, Atrogin-1 and MuRF1. The reduction of activity and expression of these proteins might ultimately lead to less muscular atrophy 21.
Mechanism of Action: GHRP-2 acts to endogenously increase growth hormone release from the pituitary. With the increase of serum growth hormone, downstream effects occur. A notable hormone that is commonly used as a surrogate for growth hormone therapy, insulin like growth factor 1 (IGF-1), is known to increase with the infusion of GHRP-2 2223. Administration of GHRP-2 results in amplification of the naturally occurring growth hormone secretion peaks, regulated by the hypothalamus and pituitary. After the release of growth hormone, a cascade of signaling events occurs in many body tissues, continuous exposure to growth hormone elicits long-term physiological changes. Of particular interest, especially in the case of the use of GHRP-2 as an alternative growth hormone therapy, hepatic production of IGF-1 occurs as result of endogenously released growth hormone from GHRP-2 2425.
GHRP-2 acts on the growth hormone secretagogue receptor (GHSR1a) in pituitary and hypothalamic tissues. The growth hormone secretagogue receptor (GHSR) is the natural receptor for the endogenous hormone Ghrelin, a stress hormone produced mainly by the lining of the stomach. This receptor among many other functions, controls and growth hormone release 24.
Drug Name: Sermorelin
Sermorelin is a drug used to stimulate the pituitary to release growth hormone.
Uses: Assessment of growth hormone deficiency (GHD), treatment of children with idiopathic growth hormone deficiency 26, adult-onset growth hormone insufficiency 27.
Pharmacologic Category: Sermorelin, is a member of the growth hormone-releasing hormone (GHRH) analogue drug class.
Other names: Geref, GRF 1-29
General Information: Sermorelin, is a 29-amino acid polypeptide containing the 1st through 29th amino acids found in endogenous human GHRH, it is the most widely used member of the GHRH analogue drug class. It can significantly promote the release of growth hormone (GH), improving the serum concentrations of GH and subsequently insulin-like growth factor 1 (IGF-1) in animals and humans 2829. Sermorelin is readily degraded after reaching the bloodstream, its biological half-life is approximately 10-20 min 30. Modification of both pulse amplitude and frequency of GH secretion are resultant after Sermorelin administration 31. Due to the biological half-life and bioavailability of Sermorelin, administration must occur periodically several times a day in multiple subcutaneous-injections 27. GHRH has been shown to be a regulator of sleep patterns and hormone secretion. GHRH elicits an increase in the amount of slow wave sleep (SWS) while augmenting GH secretion and reducing cortisol secretion 32. It has been demonstrated that a 3 mcg/kg subcutaneous-injection of Sermorelin elicits a native-GHRH GH release response 33. The requirement of an intact GH axis including a functioning pituitary, hypothalamus and a host of peripheral tissues are required for Sermorelin to exert its beneficial effects 34. This is due to the reliance on endogenous receptors controlling hormone secreting glands and tissues. More precisely, functioning growth hormone releasing hormone receptors (GHRHr) are required in a functioning anterior pituitary 33].
Mechanism of Action: Sermorelin essentially mimics the hypothalamic peptide, GHRH. Sermorelin acts directly on the pituitary stimulating the somatotroph cells ability to produce and secrete GH 35. Sermorelin increases proliferation of somatotroph cells during development 35. With the increase of serum GH, downstream effects occur. A notable hormone that is commonly used as a surrogate for growth hormone therapy, insulin like growth factor 1 (IGF-1), is known to increase with the administration of Sermorelin. IGF-I negatively regulates GHRH-mediated GH secretion 36. Sermorelin is able to influence the concert of hormonal signaling that effects the GH axis. GH secretion from the anterior pituitary is regulated by GHRH, somatostatin, and GH secretagogues. The positive and negative opposing regulation of growth hormone by GHRH and somatostatin creates a rhythmic-circadian GH secretion. GH asked by signaling target cells, most notably increasing the synthesis of IGF-1 in the liver and peripheral tissues 35 Sermorelin acts on the growth GHRHr in the pituitary to regulate cellular actives. GHRHr is the natural receptor for the endogenous hormone GHRH, a signaling hormone produced by the hypothalamus. This receptor among many other functions, controls growth hormone release, mainly by inhibition of somatostatin activity 37.
What is this medicine used for? Treatment of growth problems due to growth hormone deficiency. It works by stimulating the pituitary gland to release more natural growth hormone. It is also used for a range of medical issues including low natural growth hormone production and to promote muscle mass gain.
Key warnings before taking this medicine: Tell your doctor your medical history, especially of: thyroid problems, brain disorders (e.g., lesions) and any allergies. Discuss the risks and benefits with your doctor with use in pregnant women. It is not known whether this drug passes into breast milk. Because of the potential risk to the infant, breast-feeding while using this drug is not recommended. Consult your doctor before breast-feeding.
How is it best taken? Inject this medication subcutaneously before bedtime, or as directed by your healthcare provider.
What do I do if I miss a dose? If you miss a dose, use it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.
What are the precautions for taking this medicine? Tell your doctor of all prescription and nonprescription medication you may use, especially: corticosteroids and thyroid medications. This drug may affect the results of certain lab tests (e.g., inorganic phosphorus, alkaline phosphatase). Make sure laboratory personnel and your doctors know you use this drug. Do not start or stop any medicine without approval from your healthcare provider. Hypothyroidism: Untreated hypothyroidism can jeopardize the response to sermorelin. Thyroid hormone determinations should be performed before the initiation and during therapy. Thyroid hormone replacement therapy should be initiated when indicated. Intracranial lesions: Patients with GH deficiency secondary to an intracranial lesion were not studied in clinical trials; sermorelin treatment is not recommended in such patients. Obesity, hyperglycemia or hyperlipidemia: Subnormal GH responses have been seen in obesity and hyperglycemia, and in patients with elevated plasma fatty acids. Pregnancy and Lactation: FDA pregnancy risk category C. Exercise caution during lactation; it is not known if this drug is excreted in breast milk. Laboratory Tests: Serum levels of inorganic phosphorus, alkaline phosphatase, GH and IGF-I may increase with therapeutic use. Corticosteroids: Glucocorticoids may inhibit the response to sermorelin. Controlled studies did not indicate an interaction of sermorelin with drugs commonly used in the treatment of routine pediatric problems/illnesses. However, formal drug interaction studies have not been conducted.
Who should not take this medicine? HGH is traditionally contraindicated in individuals with: Benign intracranial hypertension (BIH), critically ill persons (e.g., after complications following open heart or abdominal surgery, multiple trauma, acute respiratory failure or similar conditions), diabetic retinopathy, persons with evidence of tumor activity; in persons with tumors, anti-tumor therapy must be completed before initiating HGH therapy, persons with known hypersensitivity to HGH or to any of its excipients, women who are pregnant, planning to become pregnant, or lactating.
What are some possible side effects of this medicine? Call your doctor for medical advice if the following side effects occur: pain/swelling/redness of the injection site (occuring in 16% fo patients). Other treatment-related adverse reactions with occurrence rates of less than 1% include . Other possible, but less common side effects of HGH are: upper respiratory conditions, nerve sensitivity, insomnia, depression, nausea, hypothyroidism, chest pain, gynecomastia, headache, flushing, dysphagia, dizziness, hyperactivity, somnolence, urticaria and sore bones. Call your health care provider immediately if you are experiencing trouble swallowing, vomiting, tightness in the chest. Antibody formation to sermorelin has been reported frequently after chronic SC administration of large doses. The clinical significance is unknown, but antibodies do not appear to affect growth or appear to be related to a specific ADR profile. No generalized allergic reactions have been reported. A temporary allergic reaction described as severe redness, swelling and urticaria at the injection sites has been reported in one patient who developed antibodies. Additionally, its use may: reduce insulin sensitivity, thereby raising blood sugar to levels which could be harmful to diabetes sufferers; and decrease Triiodothyronine (T3) levels due to its tendency to reduce the bodily levels of sodium, potassium, and phosphorous.