Endogène

Endogène, in English endogenous, is an adjective used in several disciplines to denote a process or substance originating from within a system. The term derives from Greek words meaning 'inside' and 'produced' and has been transmitted through Latin into modern languages, including French. In general use it contrasts with exogène (exogenous), meaning produced outside or triggered by external sources.

In biology and medicine, endogenous refers to factors produced by the organism itself. Examples include endogenous hormones secreted by endocrine glands, endogenous neurotransmitters, and endogenous circadian rhythms generated by the body's internal clock. Endogenous substances may act as mediators, regulators, or markers of physiological states. The term is also used to describe infections or toxins that originate within the patient’s own body or microbiome—though such usage depends on context and is more common in clinical discussion of pathophysiology.

In economics and social sciences, endogenous variables are those whose values are determined within the model by the interactions of its components, as opposed to exogenous variables whose values are imposed from outside. Endogenous growth theories seek to explain long-run development via internal mechanisms such as knowledge spillovers and investment in human capital.

In earth sciences and geology, endogenic processes originate within the Earth, including plate tectonics, volcanism, and metamorphism, while exogenic processes are driven by external forces such as weathering and erosion.

The term is used in other fields as well, often with the same core meaning: produced or arising from within a given system rather than imported from outside.