Endogeny (biology): Difference between revisions

{{for|endogeneity in econometrics|Endogeneity (econometrics)}}

[[File:1802_Examples_of_Amine_Peptide_Protein_and_Steroid_Hormone_Structure.jpg|link=https://en.wikipedia.org/wiki/File:1802_Examples_of_Amine_Peptide_Protein_and_Steroid_Hormone_Structure.jpg|alt=|thumb|445x445px|Hormones are endogenous substances secreted in the body, with different biological roles and functions]]

'''Endogenous''' substances and processes are those that originate from within a system such as an [[organism]], [[Tissue (biology)|tissue]], or [[Cell (biology)|cell]].<ref>{{cite web|url=http://dictionary.reference.com/search?q=endogenous |title=Endogenous &#124; Define Endogenous at Dictionary.com |publisher=Dictionary.reference.com |date= |accessdate=2011-07-11}}</ref> The term is chiefly used in biology but also in other fields.<ref group="nb">The term has also been applied to sociological concepts. See (Vasey 2002 p. 8). </ref>

Endogenous substances and processes contrast with [[exogenous]] ones, such as [[Drug|drugs]], which originate from outside of the organism.

== Endogenous substances ==

[[Cell signaling|Cell signalling]] systems such as [[hormone]] and [[neurotransmitter]] systems use endogenous substances. Endogenous substances can regulate sleep.<ref>{{Cite book|url=https://books.google.com/books?id=rT7clpjUwaEC|title=Biology of Sleep Substances|last=Inoue|first=Shojiro|date=1989-03-31|publisher=CRC Press|year=|isbn=9780849348228|location=|pages=|language=en}}</ref>{{Rp|1}} Examples of endogenous substances, and systems that use them, include

* The [[Endocannabinoid system|endogenous cannabinoid system]], from which the term "endocannabinoid" derives. The endocannabinoid system is important in physiology but can be modulated by exogenous phytocannabinoids originating from outside the organism, such as [[Tetrahydrocannabinol|THC]].<ref>{{Cite web|url=https://www.allure.com/story/weed-improve-sex-life|title=Here’s How Weed Use Can Improve Your Sex Life|last=Nast|first=Condé|website=Allure|language=en|access-date=2019-06-19}}</ref>

*[[Steroid|Endogenous steroids]].<ref>{{Cite book|url=https://books.google.com/books?id=7zYXBQAAQBAJ|title=Frontiers of Bioorganic Chemistry and Molecular Biology: Proceedings of the International Symposium on Frontiers of Bioorganic Chemistry and Molecular Biology, Moscow and Tashkent, USSR, 25 September - 2 October 1978|last=Ananchenko|first=S. N.|date=|publisher=Elsevier|year=1980|isbn=9781483278834|location=|pages=|language=en}}</ref>{{Rp|261}}

*[[Opioid|Endogenous opioids]], which are peptides, such as [[Enkephalin|enkephalins]] and [[endorphins]], that can modulate the opioid system.<ref>{{Cite journal|last=Akil|first=Huda|last2=Watson|first2=Stanley J.|last3=Young|first3=Elizabeth|last4=Lewis|first4=Michael E.|last5=Khachaturian|first5=Henry|last6=Walker|first6=J. Michael|date=1984|title=Endogenous Opioids: Biology and Function|url=https://doi.org/10.1146/annurev.ne.07.030184.001255|journal=Annual Review of Neuroscience|volume=7|issue=1|pages=223–255|doi=10.1146/annurev.ne.07.030184.001255|pmid=6324644}}</ref> The term "endorphin" is derived from "endogenous morphine".

* [[Nitric oxide]], which is an endogenous cell signalling molecule.<ref>{{Cite journal|last=Ignarro|first=Louis J.|date=1999-04-01|title=Nitric Oxide: A Unique Endogenous Signaling Molecule in Vascular Biology|url=https://doi.org/10.1023/A:1020150124721|journal=Bioscience Reports|language=en|volume=19|issue=2|pages=51–71|doi=10.1023/A:1020150124721|issn=1573-4935}}</ref> Nitric oxide was identified as the substance previously known as [[Endothelium-derived relaxing factor|endothelium-derived relaxing factor (EDRF)]], which was known to be an endogenous substance responsible for the relaxation of vascular [[endothelium]].

*[[Sulfur dioxide]].<ref>{{cite journal|vauthors=Chen S, Zheng S, Liu Z, Tang C, Zhao B, Du J, Jin H|date=Feb 2015|title=Endogenous sulfur dioxide protects against oleic acid-induced acute lung injury in association with inhibition of oxidative stress in rats.|journal=Lab. Invest.|volume=95|issue=2|pages=142–156|doi=10.1038/labinvest.2014.147|pmid=25581610}}</ref>

Endogenous [[transcription factor]]s are those manufactured by the cell, as distinguished from cloned transcription factors.{{Citation needed|date=June 2019}}

Endogenous substances typically have some physiological utility. However substances can also be pathologically endogenous. For example, in [[auto-brewery syndrome]], ethanol is endogenously produced within the digestive system through endogenous fermentation of sugars.

Endogeneity can, in some [[biology|biological]] systems, particularly with [[Virus|viruses]] and [[prokaryote]]s, pertain to [[DNA]] incorporated (endogenized) into the organism.<ref>{{Cite journal|last=Clément Gilbert|first=|last2=Feschotte|first2=Cédric|date=2012|title=Endogenous viruses: insights into viral evolution and impact on host biology|url=https://www.nature.com/articles/nrg3199|journal=Nature Reviews Genetics|language=en|volume=13|issue=4|pages=283–296|doi=10.1038/nrg3199|issn=1471-0064|via=}}</ref> However, because of [[homeostasis]]{{Why|date=June 2019|reason=Why does homeostasis change this?}}, discerning between internal and external influences is often difficult.{{Citation needed|date=June 2019}} [[Endogenous viral element]]s, which are [[Nucleic acid sequence|DNA sequences]] derived from [[virus]]es that are ancestrally inserted into the [[genome]]s of [[germ cell]]s.{{Citation needed|date=June 2019}} These sequences, which may be fragments of viruses or entire viral genomes ([[provirus|proviruses]]), can persist in the [[germline]], being passed on from one generation to the next as host [[allele]]s.{{Citation needed|date=June 2019}} [[Endogenous retrovirus|Endogenous retroviruses]] are a type of endogenous viral element.

== Endogenous processes ==

Endogenous effects, in conjunction with environmental influences, can change systems.<ref name=":0">{{Cite book|url=https://books.google.com/books?id=XcrrGBbT9eEC&hl=en|title=An Ecological History of Agriculture 10,000 B.C.-A.D. 10,000|last=Vasey|first=Daniel E.|date=|publisher=Purdue University Press|year=2002|isbn=9781557532725|location=|pages=|language=en}}</ref>{{Rp|8}}

Endogeny can refer to changes that originate from within a system.<ref name=":0" />{{Rp|8}} Endogenous changes can occur in social systems and can be modelled by Marxian dialectics.<ref name=":0" />{{Rp|8}}

Orthogenesis is a similar concept to endogeny but refers to changes within separate systems that results in their evolution along similar paths.<ref name=":0" />{{Rp|8}} The concept of orthogenesis has never been widely favored in evolutionary biology.<ref name=":0" />{{Rp|8}}

Examples of endogenous processes include:

* [[Senescence]] (biological aging)

* The [[menstrual cycle]]

* The self-sustained [[circadian rhythm]]s of plants and animals.{{Citation needed|date=June 2019}}

* [[Endogenous regeneration]], which refers to the ability of cells to engage in the repair and [[Regeneration (biology)#Humans|regeneration]] process.

* Endogenous [[Chronobiology|biological clocks]] and biological rhythms originating from endogenous mechanisms allow forms of biochronometry.<ref>{{Cite book|url=https://books.google.com/books?id=PaqgQ_QddoUC|title=An Introduction to Biological Rhythms|last=Palmer|first=John|date=2012-12-02|publisher=Elsevier|year=|isbn=9780323152426|location=|pages=|language=en}}</ref>{{Rp|281-282}}

Endogenous processes can also be pathological. For example, [[endogenous depression]] is an atypical type of depression caused by internal effects, such as cognitive and biological stressors.

== Endogeneity in other fields ==

<!-- Content copied from prior edit: https://en.wikipedia.org/w/index.php?title=Endogeny_(biology)&action=edit&oldid=457834105 -->

{{more citations needed section|date=June 2019}}

=== Geography ===

All processes that take place inside [[Earth]] (and other [[Planet|planets]]) are considered endogenous. They make the [[continents]] migrate, push the [[mountains]] up, and trigger [[earthquakes]] and [[volcanism]]. Endogenous processes are driven by the warmth that is produced in the core of Earth by [[radioactivity]] and [[gravity]].

=== Psychology ===

An [[emotion]] or [[behavior]] is endogenous if it is spontaneously generated from an individual's internal state.

=== Economics and finance ===

{{Main|Endogeneity (economics)}}

A variable is called '''endogenous''' if it is explained within the model in which it appears. For example, in a supply and demand model of an agricultural market, the [[price]] and quantity of trade would be the endogenous variables explained by the model; changes in the weather or in consumer tastes would be exogenous variables that might shift the supply and demand curves.

=== Political science ===

In [[political science]], something is endogenous if it is actually the result of the action for which it is generally labeled the cause{{Citation needed|date=December 2009}}. For example, ethnic violence is generally thought to be caused by ethnic division. However, endogeny would say that ethnic divisions are a result of [[ethnic violence]].

==See also==

* [[Endogeneity (econometrics)]]

* [[Endogenous preferences]]

* [[Endogenous growth theory]]

* [[Endocrine system]]

* [[Exogeny]]

==Notes==

{{reflist|group=nb}}

*{{Wiktionary-inline}}