Epinephrine

From The School of Biomedical Sciences Wiki
(Difference between revisions)
Jump to: navigation, search
(Removed some stray code. Cleaned up the text.)
Line 1: Line 1:
Epinephrine is also known as [[Adrenaline|adrenaline]]. It is a [[Steroid hormone|steroid hormone]] which is released by [[Chromaffin cells|chromaffin cells]] in the [[Adrenal gland|adrenal glands]] as part of the 'fight or flight' response. Epinephrine is an amino acid derivative of [[Tyrosine|tyrosine]] secreted from the [[Adrenal medulla|adrenal medulla]]. The polarity of the epinephrine [[Molecule|molecule]] allows it to bind to a stimulatory [[G-proteins|G protein]] which is coupled to [[Beta-adrenergenic receptor|Beta-adrenergenic receptors]] on the surface of the [[Liver|liver]]<ref>Lodish H, Berk A, Zipursky S, Mastudaira P, Balitmore D, Darnell J, Molecular Cell Biology, Section 20.3, 4th edition, W.H. Freeman, 2000</ref><span style="font-size: 11.066665649414063px;">.&nbsp;</span>Initially the G protein is inactive with guanosine diphosphate ([[GDP|GDP]]) bound. Once epinephrine binds the GDP molecule is released and guanosine triphosphate ([[GTPase activity|GTP]]) is attached, activating the G protein. The [[G protein alpha subunit|alpha subunit]] of the G protein binds to and activates [[Adenylyl cyclase|adenylyl cyclase]] catalysing the conversion of [[ATP|ATP]] to [[CAMP|cAMP]]. cAMP converts [[Phosphorylase α|phosphorylase α]] into [[Phosphorylase β|phosphorylase β]], activating protein kinase A ([[PKA|PKA]])<ref>Citric cycle, Krantz B, Principles of Biochemistry, “Principles of Metabolic Regulation” Chapter 15, Berkeley, 2008</ref>. PKA goes on to phosphorylate other target proteins making [[Glycogen synthase|glycogen synthase]] less active by [[Phosphorylation|phosphorylation]] using a phosphate from ATP resulting in less [[Glycogen|glycogen]] being synthesised<ref>Diwan J, Glycogen Metabolism, 2007 https://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb1/part2/glycogen.htm, cited on 12/11/2016</ref>.&nbsp;PKA also adds a phosphate to [[Phosphorylase kinase|phosphorylase kinase]]<ref>Diwan J, Glycogen Metabolism, 2007 https://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb1/part2/glycogen.htm, cited on 12/11/2016</ref>. This activates [[Glycogen phosphorylase|glycogen phosphorylase]], increasing breakdown of glycogen into [[Glucose|glucose]] releasing lots of energy rapidly. One epinephrine-binding molecule can cause activation of hundreds of phosphorylations through amplification of the cell signalling cascade and can produce a permanent change in [[Enzyme|enzyme]] molecules. <sup></sup>This response can be induced by stress or other stimuli in the environment and causes many physiological effects such as increased heart rate, increased blood sugar levels (due to the conversion of [[Glycogen|glycogen]] to [[Glucose|glucose]] in the [[Liver|liver]]); increased breathing rate, constriction of peripheral blood vessels and dilation of the pupils <ref>Alberts et al. (2008:G2), Molecular Biology of the Cell, 5th edition, New York: Garland Science</ref><ref>The American Society of Health-System Pharmacists (2015). https://www.nlm.nih.gov/medlineplus/druginfo/meds/a603002.html date visited 20/10/2015</ref>.  
+
Epinephrine is also known as [[Adrenaline|adrenaline]]. It is a [[Steroid hormone|steroid hormone]] which is released by [[Chromaffin cells|chromaffin cells]] in the [[Adrenal gland|adrenal glands]] as part of the 'fight or flight' response. Epinephrine is an amino acid derivative of [[Tyrosine|tyrosine]] secreted from the [[Adrenal medulla|adrenal medulla]]. The polarity of the epinephrine [[Molecule|molecule]] allows it to bind to a stimulatory [[G-proteins|G protein]] which is coupled to [[Beta-adrenergenic receptor|Beta-adrenergenic receptors]] on the surface of the [[Liver|liver]]<ref>Lodish H, Berk A, Zipursky S, Mastudaira P, Balitmore D, Darnell J, Molecular Cell Biology, Section 20.3, 4th edition, W.H. Freeman, 2000</ref>. Initially, the G protein is inactive with guanosine diphosphate ([[GDP|GDP]]) bound. Once epinephrine binds the GDP molecule is released and guanosine triphosphate ([[GTPase activity|GTP]]) is attached, activating the G protein. The [[G protein alpha subunit|alpha subunit]] of the G protein binds to and activates [[Adenylyl cyclase|adenylyl cyclase]] catalysing the conversion of [[ATP|ATP]] to [[CAMP|cAMP]]. cAMP converts [[Phosphorylase α|phosphorylase α]] into [[Phosphorylase β|phosphorylase β]], activating protein kinase A ([[PKA|PKA]])<ref>Citric cycle, Krantz B, Principles of Biochemistry, “Principles of Metabolic Regulation” Chapter 15, Berkeley, 2008</ref>. PKA goes on to phosphorylate other target proteins making [[Glycogen synthase|glycogen synthase]] less active by [[Phosphorylation|phosphorylation]] using a phosphate from ATP resulting in less [[Glycogen|glycogen]] being synthesised<ref>Diwan J, Glycogen Metabolism, 2007 https://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb1/part2/glycogen.htm, cited on 12/11/2016</ref>. PKA also adds a phosphate to [[Phosphorylase kinase|phosphorylase kinase]]<ref>Diwan J, Glycogen Metabolism, 2007 https://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb1/part2/glycogen.htm, cited on 12/11/2016</ref>. This activates [[Glycogen phosphorylase|glycogen phosphorylase]], increasing breakdown of glycogen into [[Glucose|glucose]] releasing lots of energy rapidly. One epinephrine-binding molecule can cause activation of hundreds of phosphorylations through amplification of the cell signalling cascade and can produce a permanent change in [[Enzyme|enzyme]] molecules. <sup></sup>This response can be induced by stress or other stimuli in the environment and causes many physiological effects such as increased heart rate, increased blood sugar levels (due to the conversion of [[Glycogen|glycogen]] to [[Glucose|glucose]] in the [[Liver|liver]]); increased breathing rate, constriction of peripheral blood vessels and dilation of the pupils<ref>Alberts et al. (2008:G2), Molecular Biology of the Cell, 5th edition, New York: Garland Science</ref><ref>The American Society of Health-System Pharmacists (2015). https://www.nlm.nih.gov/medlineplus/druginfo/meds/a603002.html date visited 20/10/2015</ref>.  
  
 
Epinephrine injections can cause side effects such as&nbsp;:  
 
Epinephrine injections can cause side effects such as&nbsp;:  

Revision as of 15:56, 27 November 2017

Epinephrine is also known as adrenaline. It is a steroid hormone which is released by chromaffin cells in the adrenal glands as part of the 'fight or flight' response. Epinephrine is an amino acid derivative of tyrosine secreted from the adrenal medulla. The polarity of the epinephrine molecule allows it to bind to a stimulatory G protein which is coupled to Beta-adrenergenic receptors on the surface of the liver[1]. Initially, the G protein is inactive with guanosine diphosphate (GDP) bound. Once epinephrine binds the GDP molecule is released and guanosine triphosphate (GTP) is attached, activating the G protein. The alpha subunit of the G protein binds to and activates adenylyl cyclase catalysing the conversion of ATP to cAMP. cAMP converts phosphorylase α into phosphorylase β, activating protein kinase A (PKA)[2]. PKA goes on to phosphorylate other target proteins making glycogen synthase less active by phosphorylation using a phosphate from ATP resulting in less glycogen being synthesised[3]. PKA also adds a phosphate to phosphorylase kinase[4]. This activates glycogen phosphorylase, increasing breakdown of glycogen into glucose releasing lots of energy rapidly. One epinephrine-binding molecule can cause activation of hundreds of phosphorylations through amplification of the cell signalling cascade and can produce a permanent change in enzyme molecules. This response can be induced by stress or other stimuli in the environment and causes many physiological effects such as increased heart rate, increased blood sugar levels (due to the conversion of glycogen to glucose in the liver); increased breathing rate, constriction of peripheral blood vessels and dilation of the pupils[5][6].

Epinephrine injections can cause side effects such as :

Reference

  1. Lodish H, Berk A, Zipursky S, Mastudaira P, Balitmore D, Darnell J, Molecular Cell Biology, Section 20.3, 4th edition, W.H. Freeman, 2000
  2. Citric cycle, Krantz B, Principles of Biochemistry, “Principles of Metabolic Regulation” Chapter 15, Berkeley, 2008
  3. Diwan J, Glycogen Metabolism, 2007 https://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb1/part2/glycogen.htm, cited on 12/11/2016
  4. Diwan J, Glycogen Metabolism, 2007 https://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb1/part2/glycogen.htm, cited on 12/11/2016
  5. Alberts et al. (2008:G2), Molecular Biology of the Cell, 5th edition, New York: Garland Science
  6. The American Society of Health-System Pharmacists (2015). https://www.nlm.nih.gov/medlineplus/druginfo/meds/a603002.html date visited 20/10/2015
  7. American Society of Health-System Pharmacists (2012). https://www.nlm.nih.gov/medlineplus/druginfo/meds/a603002.html
.


Personal tools
Namespaces
Variants
Actions
Navigation
Toolbox