endogenous

adjective

en·​dog·​e·​nous en-ˈdä-jə-nəs 

1

: growing or produced by growth from deep tissue

endogenous plant roots

2

a

: caused by factors inside the organism or system

suffered from endogenous depression

endogenous business cycles

b

: produced or synthesized within the organism or system

an endogenous hormone

endogenously adverb

Did you know?

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

This dynamic begins in infancy: babies literally cannot modulate their stress system without nurturing touch from caregivers, which releases endogenous opioids and oxytocin, creating a sense of comfort and safety. —Maia Szalavitz, Scientific American, 17 Sep. 2024

And during scary or stressful experiences, endogenous, or self-generated, opioids known as endorphins and enkephalins are released in the brain. —Maia Szalavitz, Scientific American, 17 Sep. 2024

There are two primary types of Cushing syndrome: exogenous and endogenous, which are differentiated based on the cause of the disorder. —Madeline Nguyen, The Arizona Republic, 12 June 2024

In addition to being the active ingredient in ayahuasca, DMT is an endogenous molecule synthesized naturally in mammalian brains. —Jon Brodkin, Ars Technica, 2 Oct. 2023

Word History

First Known Use

1830, in the meaning defined at sense 1

Medical Definition

endogenous

adjective

en·​dog·​e·​nous en-ˈdäj-ə-nəs 

variants also endogenic

ˌen-də-ˈjen-ik 

1

: growing from or on the inside

endogenous spores

2

: caused by factors within the body or mind or arising from internal structural or functional causes

endogenous malnutrition

endogenous psychic depression

3

: relating to or produced by metabolic synthesis in the body

endogenous opioids

endogenous amino acids

compare exogenous

endogenously adverb