Open main menu
Home
Random
Recent changes
Special pages
Community portal
Preferences
About Wikipedia
Disclaimers
Incubator escapee wiki
Search
User menu
Talk
Dark mode
Contributions
Create account
Log in
Editing
Glycogen
(section)
Warning:
You are not logged in. Your IP address will be publicly visible if you make any edits. If you
log in
or
create an account
, your edits will be attributed to your username, along with other benefits.
Anti-spam check. Do
not
fill this in!
==Clinical relevance== ===Disorders of glycogen metabolism=== The most common disease in which glycogen [[metabolism]] becomes abnormal is [[diabetes]], in which, because of abnormal amounts of insulin, liver glycogen can be abnormally accumulated or depleted. Restoration of normal glucose metabolism usually normalizes glycogen metabolism, as well. In [[hypoglycemia]] caused by excessive insulin, liver glycogen levels are high, but the high insulin levels prevent the [[glycogenolysis]] necessary to maintain normal blood sugar levels. [[Glucagon]] is a common treatment for this type of hypoglycemia. Various [[inborn errors of carbohydrate metabolism]] are caused by deficiencies of enzymes or transport proteins necessary for glycogen synthesis or breakdown. These are collectively referred to as [[glycogen storage disease]]s. ===Glycogen depletion and endurance exercise=== Long-distance athletes, such as [[Marathon (sport)|marathon]] runners, [[Cross-country skiing|cross-country skiers]], and [[cyclist]]s, often experience glycogen depletion, where almost all of the athlete's glycogen stores are depleted after long periods of exertion without sufficient carbohydrate consumption. This phenomenon is referred to as "[[hitting the wall]]" in running and "bonking" in cycling. Glycogen depletion can be forestalled in three possible ways: * First, during exercise, carbohydrates with the highest possible rate of conversion to blood glucose (high [[glycemic index]]) are ingested continuously. The best possible outcome of this strategy replaces about 35% of glucose consumed at heart rates above about 80% of maximum. * Second, through endurance training adaptations and specialized regimens (e.g. fasting, low-intensity endurance training), the body can condition [[Myocyte#type I anchor|type I muscle]] fibers to improve both fuel use efficiency and workload capacity to increase the percentage of fatty acids used as fuel,<ref>{{cite web |title=Methods of endurance training, Part 1 |date=2009-10-30 |url=http://www.bodyrecomposition.com/training/methods-of-endurance-training-part-1.html |access-date=1 August 2013 |archive-date=22 July 2018 |archive-url=https://web.archive.org/web/20180722203112/https://bodyrecomposition.com/training/methods-of-endurance-training-part-1.html/ |url-status=dead}}</ref><ref>{{cite web |title=Steady state vs. tempo training and fat loss |date=2008-06-02 |url=http://www.bodyrecomposition.com/fat-loss/qa-steady-state-vs-tempo-training-and-fat-loss.html |access-date=1 August 2013 |archive-date=5 September 2017 |archive-url=https://web.archive.org/web/20170905054006/https://www.bodyrecomposition.com/fat-loss/qa-steady-state-vs-tempo-training-and-fat-loss.html/ |url-status=dead }}</ref> sparing carbohydrate use from all sources. * Third, by consuming large quantities of carbohydrates after depleting glycogen stores as a result of exercise or diet, the body can increase storage capacity of intramuscular glycogen stores.<ref name="Jensen 2020"/><ref>{{cite web |last=McDonald |first=Lyle |date=2012-07-25 |title=Research review: An in-depth look into carbing up on the cyclical ketogenic diet |url=http://www.directlyfitness.com/store/carbing-cyclical-ketogenic-diet/ |access-date=19 February 2017 |archive-date=11 November 2020 |archive-url=https://web.archive.org/web/20201111194513/http://www.directlyfitness.com/store/carbing-cyclical-ketogenic-diet/ |url-status=dead }}</ref><ref>{{cite book |last=McDonald |first=Lyle |year=1998 |title=The Ketogenic Diet: A complete guide for the dieter and the practitioner |publisher=Lyle McDonald}}</ref><ref name="pmid5123660">{{cite journal |vauthors=Costill DL, Bowers R, Branam G, Sparks K |date=December 1971 |title=Muscle glycogen utilization during prolonged exercise on successive days |journal=J Appl Physiol |volume=31 |issue=6 |pages=834β838 |pmid=5123660 |doi=10.1152/jappl.1971.31.6.834}}</ref> This process is known as [[carbohydrate loading]]. In general, glycemic index of carbohydrate source does not matter since muscular insulin sensitivity is increased as a result of temporary glycogen depletion.<ref name="pmid3538900">{{cite journal |vauthors=Zorzano A, Balon TW, Goodman MN, Ruderman NB |date=December 1986 |title=Glycogen depletion and increased insulin sensitivity and responsiveness in muscle after exercise |journal=Am. J. Physiol. |volume=251 |issue=6, Part 1 |pages=E664βE669 |pmid=3538900 |doi=10.1152/ajpendo.1986.251.6.E664}}</ref><ref>{{cite book |last=McDonald |first=Lyle |year=2003 |title=The Ultimate Diet 2.0 |publisher=Lyle McDonald}}</ref> When athletes ingest both carbohydrate and [[caffeine]] following exhaustive exercise, their glycogen stores tend to be replenished more rapidly;<ref>{{cite journal |last1=Pedersen |first1=D.J. |last2=Lessard |first2=S.J. |last3=Coffey |first3=V.G. |display-authors=etal |date=July 2008 |title=High rates of muscle glycogen resynthesis after exhaustive exercise when carbohydrate is coingested with caffeine |journal=Journal of Applied Physiology |volume=105 |issue=1 |pages=7β13 |pmid=18467543 |doi=10.1152/japplphysiol.01121.2007}}</ref><ref name="Recovery nutrition review">{{cite journal |last1=Beelen |first1=M. |last2=Burke |first2=L.M. |last3=Gibala |first3=M.J. |last4=van Loon |first4=L.J.C. |date=December 2010 |title=Nutritional strategies to promote post-exercise recovery |journal=International Journal of Sport Nutrition and Exercise Metabolism |volume=20 |issue=6 |pages=515β532 |pmid=21116024 |s2cid=13748227 |doi=10.1123/ijsnem.20.6.515}}</ref> however, the minimum dose of caffeine at which there is a [[clinically significant]] effect on glycogen repletion has not been established.<ref name="Recovery nutrition review" /> ===Nanomedicine=== Glycogen [[nanoparticle]]s have been investigated as potential [[drug delivery systems]].<ref>{{cite journal |title=Glycogen as a Building Block for Advanced Biological Materials |author1=Quinn A. Besford |author2=Francesca Cavalieri |author3=Frank Caruso |date=7 May 2020 |orig-year=16 October 2019 |journal=Advanced Materials |volume=32 |issue=18 |at=1904625 |doi=10.1002/adma.201904625|pmid=31617264 |bibcode=2020AdM....3204625B |hdl=11343/230737 |s2cid=204738366 |hdl-access=free }}</ref>
Edit summary
(Briefly describe your changes)
By publishing changes, you agree to the
Terms of Use
, and you irrevocably agree to release your contribution under the
CC BY-SA 4.0 License
and the
GFDL
. You agree that a hyperlink or URL is sufficient attribution under the Creative Commons license.
Cancel
Editing help
(opens in new window)