resecretion

Resecretion is a cellular process in which substances that have been secreted by a cell are taken back into the cell or into the lumen and then released again through a renewed secretory event. It can serve to modify the composition of secretions, regulate luminal environments, or fine‑tune the timing and location of release.

In many epithelia, resecretion involves transcytosis and recycling pathways. Secreted cargo may be reabsorbed at one membrane domain and trafficked through endosomal compartments, such as recycling endosomes, before being exocytosed at the same or a different surface. This routing often relies on vesicle trafficking proteins, including SNAREs for membrane fusion and Rab GTPases (for example Rab11) that coordinate recycling routes. The process can be modulated by physiological cues, cell polarity, and the organization of the secretory machinery.

Contexts where resecretion has been discussed include secretory epithelia of the airway, gastrointestinal tract, and reproductive tissues, as well as certain neuronal and endocrine contexts where recycled secretory products are re-released. Functions attributed to resecretion include maintaining appropriate luminal ion and water balance, regulating mucus or other protective secretions, and enabling rapid adjustments to secretory output in response to changing demands.

Terminology surrounding resecretion varies across disciplines. In some literature it is used to describe recycling and re-release of secreted molecules via transcytotic pathways; in others it denotes intracellular reprocessing of secretory cargo before final secretion. As a result, precise definitions are context-dependent.

See also: secretion, transcytosis, vesicle trafficking, endocytosis.