Growth Hormone (1-43), human (Synonyms: H2N-Phe-Pro-Thr-Ile-Pro-Leu-Ser-Arg-Leu-Phe-Asp-Asn-Ala-Met-Leu-Arg-Ala-His-Arg-Leu-His-Gln-Leu-Ala-Phe-Asp-Thr-Tyr-Gln-Glu-Phe-Glu-Glu-Ala-Tyr-Ile-Pro-Lys-Glu-Gln-Lys-Tyr-Ser-OH )

Growth Hormone (1-43), human (C₂₄₀H₃₅₈N₆₂O₆₇S₁), a peptide with the sequence H2N-FPTIPLSRLFDNAMLRAHRLHQLAFDTYQEFEEAYIPKEQKY

S-OH, MW= 5216.2. Growth hormone (GH or HGH), also known as somatotropin or somatropin, is a peptide hormone that stimulates growth, cell reproduction and regeneration in humans and other animals. It is a type of mitogen which is specific only to certain kinds of cells. Growth hormone is a 191-amino acid, single-chain polypeptide that is synthesized, stored, and secreted by somatotropic cells within the lateral wings of the anterior pituitary gland.Growth hormone is used as a prescription drug in medicine to treat children's growth disorders and adult growth hormone deficiency⁽¹⁾. Effects of growth hormone on the tissues of the body can generally be described as anabolic (building up). Like most other protein hormones, GH acts by interacting with a specific receptor on the surface of cells.Because polypeptide hormones are not fat-soluble, they cannot penetrate cell membranes. Thus, GH exerts some of its effects by binding to receptors on target cells, where it activates the MAPK/ERK pathway⁽²⁾.Through this mechanism GH directly stimulates division and multiplication of chondrocytes of cartilage.GH also stimulates, through the JAK-STAT signaling pathway,the production of insulin-like growth factor 1 (IGF-1, formerly known as somatomedin C), a hormone homologous to proinsulin⁽³⁾.The liver is a major target organ of GH for this process and is the principal site of IGF-1 production. IGF-1 has growth-stimulating effects on a wide variety of tissues. Additional IGF-1 is generated within target tissues, making it what appears to be both an endocrine and an autocrine/paracrine hormone. IGF-1 also has stimulatory effects on osteoblast and chondrocyte activity to promote bone growth.

Figure1  the structures of Growth Hormone

Figure 2  Mechanisms of Growth Hormone regulaltion

Ref:

1. Powers M (2005). "Performance-Enhancing Drugs". In Leaver-Dunn D, Houglum J, Harrelson GL. Principles of Pharmacology for Athletic Trainers. Slack Incorporated. pp. 331–332.

2. Binder G, Wittekindt N, Ranke MB (February 2007). "Noonan Syndrome: Genetics and Responsiveness to Growth Hormone Therapy". Horm Res 67 (Supplement 1): 45–49.

3. Actions of Anterior Pituitary Hormones: Physiologic Actions of GH". Medical College of Georgia. 2007.