en·​dog·​e·​nous en-ˈdä-jə-nəs How to pronounce endogenous (audio)
: growing or produced by growth from deep tissue
endogenous plant roots
: caused by factors inside the organism or system
suffered from endogenous depression
endogenous business cycles
: produced or synthesized within the organism or system
an endogenous hormone
endogenously adverb

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When biologists need to make a distinction between things that are produced within a cell or organ and things that affect it from the outside, they use the terms endogenous and exogenous. It used to be thought, for instance, that mutations in cells always resulted from exogenous causes, until it was discovered that substances in the body, including those called oxidants, could cause them endogenously as well. "Circadian rhythms"—the regular cycles, roughly 24 hours in length, that plants, animals, and humans rely on to regulate their days—are endogenously generated and don't actually depend on the sun for their timing.

Examples of endogenous in a Sentence

Recent Examples on the Web Mainstream endogenous growth models link technological improvements with the pool of resources that are thrown at solving problems. Quora, Forbes, 16 Feb. 2024 It’s believed to work by activating endogenous TGF-beta 1, which is a protein that affects cell growth and division. Allison Futterman, Discover Magazine, 4 Jan. 2024 This is in part because of the pathogen cargo such organs can transfer: Most pigs carry endogenous retroviruses, which can in theory lead to unpredictable illnesses in human recipients. Elizabeth Svoboda, Discover Magazine, 3 Dec. 2023 If so, that would strengthen the case for a subsurface ocean origin, as Enceladus’ vapor also contains some of the same salts found on the surface of Ganymede, and these salts are considered endogenous. Elizabeth Rayne, Ars Technica, 14 Nov. 2023 An additional 59 edits were made to some of the donor animals to inactivate endogenous retroviruses, which are found in pig DNA. Emily Mullin, WIRED, 11 Oct. 2023 The porcine genome contains 40 to 70 copies of DNA from porcine endogenous retroviruses (PERV) that are harmless to modern pigs but could be reactivated in humans. Shi En Kim, Scientific American, 11 Oct. 2023 Additionally, monkeys are thought to be immune to endogenous pig viruses. Shi En Kim, Scientific American, 11 Oct. 2023 Researchers have shown that crying releases oxytocin and endogenous opioids (a.k.a. endorphins), the feel-good chemicals that help ease emotional and physical pain, according to Harvard Medical School. Christine Giordano, Women's Health, 27 Aug. 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'endogenous.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1830, in the meaning defined at sense 1

Time Traveler
The first known use of endogenous was in 1830

Dictionary Entries Near endogenous

Cite this Entry

“Endogenous.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/endogenous. Accessed 3 Mar. 2024.

Medical Definition


en·​dog·​e·​nous en-ˈdäj-ə-nəs How to pronounce endogenous (audio)
variants also endogenic
: growing from or on the inside
endogenous spores
: caused by factors within the body or mind or arising from internal structural or functional causes
endogenous malnutrition
endogenous psychic depression
: relating to or produced by metabolic synthesis in the body
endogenous opioids
endogenous amino acids
compare exogenous
endogenously adverb

More from Merriam-Webster on endogenous

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