Paracrine signaling is when short-lived signal molecules are released into the extracellular fluid and influence neighboring cells. Like direct contact, paracrine signaling plays an important role in early development, coordinating the activities of clusters of neighboring cells. The immune response in vertebrates also involves paracrine signaling between immune cells.
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http://media.pearsoncmg.com/bc/bc_0media_bio/blast/index.htm?signaling_paracrine
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http://media.pearsoncmg.com/bc/bc_0media_bio/blast/index.htm?signaling_paracrine