<prompt> Mediator present in mast cells isHistamineEncephalinCalmodulinNone of these  <response>: Mast cells release several different substances. Among them areHistamineSlow-reacting substance of anaphylaxis which is a mixture of leukotrienesEosinophilic chemotactic factorBradykininRef: Guyton and Hall textbook of medical physiology 13th edition. Page:554 