Sandbox Reserved 1661: Difference between revisions
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== Functions == | == Functions == | ||
Somatropin plays an important role in physiological environments such as: increasing muscle mass, reducing fat mass, providing the energy necessary for tissue growth, maintaining the right level of glucose and lipids and the development of the individual's body <ref name="ncbi">PMID:22291494</ref>. It acts directly on a cell surface or indirectly. In the second case, somatotropin stimulates tissues such as the liver, which in turn allows the synthesis and secretion of [https://en.wikipedia.org/wiki/Insulin-like_growth_factor_1 IGF-1], thus enabling the development of cell growth, tissue, bone and thus the linear growth of the individual.<ref name="britannica"> Utiger, R. D. and other Encyclopedia Britannica Contributors (1998), Insulin-like growth factor. Science, Chemistry.</ref> | Somatropin plays an important role in physiological environments such as: increasing muscle mass, reducing fat mass, providing the energy necessary for tissue growth, maintaining the right level of glucose and lipids and the development of the individual's body <ref name="ncbi">PMID:22291494</ref>. It acts directly on a cell surface or indirectly. In the second case, somatotropin stimulates tissues such as the liver, which in turn allows the synthesis and secretion of [https://en.wikipedia.org/wiki/Insulin-like_growth_factor_1 IGF-1], thus enabling the development of cell growth, tissue, bone and thus the linear growth of the individual.<ref name="britannica"> Utiger, R. D. and other Encyclopedia Britannica Contributors (1998), Insulin-like growth factor. Science, Chemistry.</ref> | ||
The GH regulates direct or indirect anabolic and growth promoting actions. Through direct regulation GH increases the amino acid uptake, the RNA- ,protein- and cartilage-synthesis and muscle growth. These regulations are often mediated by IFG. [https://doi.org/10.1016/j.ygcen.2017.07.028 ] However, the GH is also able to regulate catabolic actions. Thus it stimulates the breakdown of lipids ([https://en.wikipedia.org/wiki/Lipolysis lipolysis] as is evident by increased fatty acids. A lack of GH is therefore associated with an increased lipid deposit. [https://doi.org/10.1016/j.ygcen.2017.07.028 ] | |||
== Structure == | == Structure == | ||
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Several GH variants with modified N-terminus were explored to learn more about the behaviour of the binding of the receptor molecule. A GH with an extension of Methionin on the N-terminus behave identical to an authentic GH in assays. The small, neutral amino acid without any side chains has no apparent effect on the binding of the receptor. In contrast, a removal of 13 amino acids at the N-terminus results in reduced binding activity to somatogenic receptors and decreased biological activity, because the amino acids 1 to 16 are involved in the binding site 2. But the other part of the binding site (with Trp103, Asp116 and Glu119 from helix 3) of the hGH molecule are intact and available for binding of the receptor. The N-terminus is required for full biological activity, however, additions still deletions can not completly abolish the functions of the molecule. <ref name="pubMed">PMID:17584122</ref> | Several GH variants with modified N-terminus were explored to learn more about the behaviour of the binding of the receptor molecule. A GH with an extension of Methionin on the N-terminus behave identical to an authentic GH in assays. The small, neutral amino acid without any side chains has no apparent effect on the binding of the receptor. In contrast, a removal of 13 amino acids at the N-terminus results in reduced binding activity to somatogenic receptors and decreased biological activity, because the amino acids 1 to 16 are involved in the binding site 2. But the other part of the binding site (with Trp103, Asp116 and Glu119 from helix 3) of the hGH molecule are intact and available for binding of the receptor. The N-terminus is required for full biological activity, however, additions still deletions can not completly abolish the functions of the molecule. <ref name="pubMed">PMID:17584122</ref> | ||
The hormone-binding extracellular domain consists of 250 amino acids, including several cysteine residues which are conserved and can form disulphide bridges.The intracellular domain of the receptor is made up of 350 amino acids, it represents the least conserved region and is made up of 10 tyrosine residues likely to be phosphorylated by tyrosine kinase ([https://en.wikipedia.org/wiki/Janus_kinase_2 JAK2]), during the formation of the GH-receptor complex. A reaction cascade involving kinase enzymes is then activated, allowing the expression of certain genes coding for proteins or not, necessary for biological activity. It therefore controls the expression of certain genes such as the gene coding for the IGF-1 factor. The liver and adipose tissue being important targets for GH, it therefore contributes to [https://en.wikipedia.org/wiki/Homeostasis#:~:text=The%20neuroendocrine%20system%20is%20the,hypothalamic%20interconnections%20to%20other%20glands. metabolic homeostasis].<ref name="m/s"/> | The hormone-binding extracellular domain consists of 250 amino acids, including several cysteine residues which are conserved and can form disulphide bridges.The intracellular domain of the receptor is made up of 350 amino acids, it represents the least conserved region and is made up of 10 tyrosine residues likely to be phosphorylated by tyrosine kinase ([https://en.wikipedia.org/wiki/Janus_kinase_2 JAK2]), during the formation of the GH-receptor complex. A reaction cascade involving kinase enzymes is then activated, allowing the expression of certain genes coding for proteins or not, necessary for biological activity. It therefore controls the expression of certain genes such as the gene coding for the IGF-1 factor. The liver and adipose tissue being important targets for GH, it therefore contributes to [https://en.wikipedia.org/wiki/Homeostasis#:~:text=The%20neuroendocrine%20system%20is%20the,hypothalamic%20interconnections%20to%20other%20glands. metabolic homeostasis].<ref name="m/s"/> [https://doi.org/10.1016/j.ygcen.2017.07.028 ] | ||
== Dieseas and treatments == | == Dieseas and treatments == | ||
