Insulin: Difference between revisions
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Insulin is a [[Hormone|hormone]]. Its main function is the regulation of blood sugar levels, by causing the [[Liver|liver]] and [[Muscle|muscles]] to increase uptake of [[Glucose|glucose]] <ref name="OMIM">http://www.ncbi.nlm.nih.gov/omim/176730</ref>. Insulin is produced from a single [[Gene|gene]] which codes for the [[Peptide|peptide]] [[Proinsulin|proinsulin]]; a precursor [[Molecule|molecule]]. [[Mutation|Mutations]] in this [[Gene|gene]] can result in a faulty [[Protein|protein]]; causing type 1 [[Diabetes|diabetes]] or a possible predisposition to type 2 [[Diabetes|diabetes]] <ref>http://www.ncbi.nlm.nih.gov/omim/176730</ref><ref>http://www.ncbi.nlm.nih.gov/pubmed/20806184</ref>.<br> | Insulin is a [[Hormone|hormone]]. Its main function is the regulation of blood sugar levels, by causing the [[Liver|liver]] and [[Muscle|muscles]] to increase uptake of [[Glucose|glucose]] <ref name="OMIM">http://www.ncbi.nlm.nih.gov/omim/176730</ref>. Insulin is produced from a single [[Gene|gene]] which codes for the [[Peptide|peptide]] [[Proinsulin|proinsulin]]; a precursor [[Molecule|molecule]]. [[Mutation|Mutations]] in this [[Gene|gene]] can result in a faulty [[Protein|protein]]; causing type 1 [[Diabetes|diabetes]] or a possible predisposition to type 2 [[Diabetes|diabetes]] <ref>http://www.ncbi.nlm.nih.gov/omim/176730</ref><ref>http://www.ncbi.nlm.nih.gov/pubmed/20806184</ref>.<br> | ||
Insulin regulates the [[Blood|blood]] [[Glucose|glucose]] levels in different ways. It enhances the [[Glucose|glucose]] transport at a cellular level by stimulation of the [[Glucose transporters|glucose transporter]] ([[Glucose transporters|GLUT]]) family. | Insulin regulates the [[Blood|blood]] [[Glucose|glucose]] levels in different ways. It enhances the [[Glucose|glucose]] transport at a cellular level by stimulation of the [[Glucose transporters|glucose transporter]] ([[Glucose transporters|GLUT]]) family. | ||
Insulin also has an effect on [[Gene|gene]] expression which is up or down regulated in the [[Homeostasis|homeostasis]] process to maintain the optimum [[Blood|blood]] [[Glucose|glucose]] levels. | Insulin also has an effect on [[Gene|gene]] expression which is up or down regulated in the [[Homeostasis|homeostasis]] process to maintain the optimum [[Blood|blood]] [[Glucose|glucose]] levels. | ||
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Insulin is released by the beta-cells of the [[Pancreas|pancreas]].<br> | Insulin is released by the beta-cells of the [[Pancreas|pancreas]].<br> | ||
=== Insulin stimulates glycogen synthesis === | === Insulin stimulates glycogen synthesis === | ||
When blood sugar levels are high, insulin binds to a tyrosine kinase receptor. Binding of insulin triggers a [[Phosphorylation cascade|phosphorylation cascade]], preventing [[Phosphorylation|phosphorylation]] of [[Glycogen synthase|glycogen synthase]] as this inactivates it's activity <ref>Berg J., Tymoczko J and Stryer L. (2007) Biochemistry, 6th edition, New York: WH Freeman.fckLR</ref>.<br> | When blood sugar levels are high, insulin binds to a tyrosine kinase receptor. Binding of insulin triggers a [[Phosphorylation cascade|phosphorylation cascade]], preventing [[Phosphorylation|phosphorylation]] of [[Glycogen synthase|glycogen synthase]] as this inactivates it's activity <ref>Berg J., Tymoczko J and Stryer L. (2007) Biochemistry, 6th edition, New York: WH Freeman.fckLR</ref>.<br> | ||
Insulin acts antagonistically to the hormone [[Glucagon|glucagon]], which acts on glycogen storage in response to low blood sugar levels.<ref>Berg J., Tymoczko J and Stryer L. (2007) Biochemistry, 6th edition, New York: WH Freeman.fckLR</ref>This serves as an effective [[Homeostatis|homeostasis]] mechanism. <br> | |||
=== References === | === References === | ||
<references /> | <references /> | ||
Revision as of 16:22, 10 January 2011
Insulin is a hormone. Its main function is the regulation of blood sugar levels, by causing the liver and muscles to increase uptake of glucose [1]. Insulin is produced from a single gene which codes for the peptide proinsulin; a precursor molecule. Mutations in this gene can result in a faulty protein; causing type 1 diabetes or a possible predisposition to type 2 diabetes [2][3].
Insulin regulates the blood glucose levels in different ways. It enhances the glucose transport at a cellular level by stimulation of the glucose transporter (GLUT) family.
Insulin also has an effect on gene expression which is up or down regulated in the homeostasis process to maintain the optimum blood glucose levels.
Insulin is released by the beta-cells of the pancreas.
Insulin stimulates glycogen synthesis
When blood sugar levels are high, insulin binds to a tyrosine kinase receptor. Binding of insulin triggers a phosphorylation cascade, preventing phosphorylation of glycogen synthase as this inactivates it's activity [4].
Insulin acts antagonistically to the hormone glucagon, which acts on glycogen storage in response to low blood sugar levels.[5]This serves as an effective homeostasis mechanism.
References
- ↑ http://www.ncbi.nlm.nih.gov/omim/176730
- ↑ http://www.ncbi.nlm.nih.gov/omim/176730
- ↑ http://www.ncbi.nlm.nih.gov/pubmed/20806184
- ↑ Berg J., Tymoczko J and Stryer L. (2007) Biochemistry, 6th edition, New York: WH Freeman.fckLR
- ↑ Berg J., Tymoczko J and Stryer L. (2007) Biochemistry, 6th edition, New York: WH Freeman.fckLR