What does exocytotic mean?
Exocytotic is an adjective used almost entirely within cell biology to describe processes, pathways, vesicles, or events connected with exocytosis — the mechanism by which a cell exports material. In exocytosis, substances such as proteins, neurotransmitters, or hormones are packaged into small membrane-bound sacs called vesicles; these vesicles travel to the cell's outer membrane and fuse with it, releasing their contents to the exterior. An exocytotic event is therefore one instance of this export process, while an exocytotic pathway refers to the regulated route cargo takes from its point of packaging to the cell surface. The word appears constantly in research on neurons, where exocytotic release of neurotransmitter underlies all communication between nerve cells, and in studies of hormone secretion and immune response. Its antonymic counterpart is endocytotic, describing the reverse traffic of material entering the cell. Outside scientific writing the term is rare, but for anyone reading modern biology it is indispensable vocabulary.
adjectiveRelating to or involving exocytosis, the process by which a cell transports material enclosed in vesicles out of the cell by fusing the vesicle membrane with the cell membrane.
- Relating to or involving exocytosis, the cellular process of releasing material via vesicle fusion with the plasma membrane.
"Neurotransmitter release depends on exocytotic fusion of synaptic vesicles with the presynaptic membrane."
"Insulin secretion occurs through exocytotic release of granules from pancreatic beta cells."
"The researchers measured exocytotic activity using fluorescent dyes that mark vesicle fusion events."
Every thought you've ever had rode on exocytotic events — each neural impulse fires neurotransmitters through this precise membrane-fusing mechanism.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of exocytotic
Exocytotic derives from exocytosis, a term coined in the early 1960s from Greek roots: exo-, meaning 'outside', combined with cytosis, built on kytos, the Greek word for a hollow vessel or cell. The adjective simply adds the standard -ic suffix to form a relational term. It shares its roots with a broad family of biological vocabulary, including cytology and cytoplasm on the kytos side, and words like exoskeleton and exocrine on the exo- side. The term entered English as scientists resolved how cells move large molecules across their membranes without breaching them.
Related word forms
How exocytotic is actually used
A technical term used almost exclusively in cell biology, neuroscience, and physiology; it rarely appears outside scientific literature and is typically found attributively before nouns such as 'pathway', 'release', 'vesicle', or 'fusion'.
Easily confused with exocytotic
Endocytotic describes the opposite process, in which a cell brings material in by engulfing it, whereas exocytotic describes material being exported out of the cell.