- 1. C. Sherrington term for a peripheral tissue that receives nerve impulses and reacts by contraction (muscle), secretion (gland), or a discharge of electricity (electric organ of certain bony fishes). 2. A small metabolic molecule that by combining with a repressor gene depresses the activity of an operon. 3. A small molecule that binds to a protein and, in so doing, alters the activity of that protein. 4. A substance, technique, procedure, or individual that causes an effect. [L. producer]
* * *ef·fec·tor i-'fek-tər, -.tȯ(ə)r n1) a bodily organ (as a gland or muscle) that becomes active in response to stimulation2) a molecule (as an inducer, a corepressor, or an enzyme) that activates, controls, or inactivates a process or action (as protein synthesis or the release of a second messenger)
* * *n.any structure or agent that brings about activity in a muscle or gland, such as a motor nerve that causes muscular contraction or glandular secretion. The term is also used for the muscle or gland itself.
* * *ef·fec·tor (ə-fekґtər) 1. an agent that mediates a specific effect, e.g., an allosteric effector or an effector cell. 2. an organ that produces an effect, e.g., contraction or secretion, in response to nerve stimulation. Called also effector organ.
Medical dictionary. 2011.