The lingual serous glands of rat tongue, the Ebner glands, secrete a potent acid lipase that acts in the stomach where it initiates the digestion of dietary fat. The factors affecting its secretion were studied ‘in vitro’ on Ebner slices. The lipolytic activity was measured in the incubation medium using tributyrine as substrate and by titration at pH: 5.4. Cholecystokinin (10−9M) and carbachol (10−5M) efficiently stimulated lipase secretion (3 fold over basal rate). The parasympathetic agent trigered secretion involving a calcium dependent system. Atropin (10−4M) blocked this cholinergic effect by about 40. Lipase secretion was stimulated by epinephrine and isoproterenol. Propranolol (β-antagonist) inhibited the adrenergic stimulation, while phentolamine was ineffective. The inhibitory effect of the selective {ie293-1} (Betaxolol) and the lack of effect of the selective {ie293-2} (ICI 118551) suggest the participation of {ie293-3} in the secretion
展开▼
