Endocrine signaling is when long-lived hormones enter the circulatory system and are carried to target cells some distance away. The longer lived signal molecules, which may affect cells very distant from the releasing cell, are called hormones.
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http://media.pearsoncmg.com/bc/bc_0media_bio/blast/index.htm?signaling_endocrine
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http://media.pearsoncmg.com/bc/bc_0media_bio/blast/index.htm?signaling_endocrine