sentence: For two mouse enteroendocrine cell lines , STC-1 and GLUTag expressing both FFAR1 and FFAR4 , TUG-891 addition caused an increase in GLP-1 secretion similar to aLa , while a selective FFA1 receptor agonist only marginally increased GLP-1 secretion and an FFA1 receptor antagonist only slightly decreased the amount of GLP-1 induced by aLa .