The Collaborative International Dictionary of English v.0.48:

Introducer \In`tro*du"cer\, n.
   One who, or that which, introduces.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

66 Moby Thesaurus words for "introducer":
   agent, alterant, alterative, alterer, ancestors, apprentice,
   architect, artificer, artist, author, begetter, beginner, builder,
   catalyst, catalytic agent, conceiver, constructor, craftsman,
   creator, designer, deviser, discoverer, effector, engenderer,
   engineer, executor, executrix, father, ferment, founder, generator,
   grower, inaugurator, industrialist, initiator, innovationist,
   innovator, instigator, institutor, inventor, journeyman, leaven,
   maker, manufacturer, master, master craftsman, modificator,
   modifier, mother, organizer, original, originator, past master,
   planner, precursor, prime mover, producer, raiser, realizer,
   shaper, sire, smith, transformer, transmogrifier, wright, yeast