Effect of fatty acids on the stimulated gastric secretion in man

Solutions and emulsions of sodium or potassium salts in a series of saturated fatty acids from C8 to C18 were given in a dose of 0.5 g intraduodenally to healthy males or patients with healed duodenal ulcer. A double-lumen Sarles tube with a balloon placed in the proximal duodenum was used. The substances were instilled after a plateau of gastric acid secretion induced by a continuous infusion of pentagastrin was reached. In order to exclude unspecific effects, the test solutions were adjusted to a pH around 7.0 and to plasma isosmolality. Compared with the other tested substances, the emulsion of 0.5 g sodium-oleate was the most effective in inhibiting the stimulated gastric acid secretion. Sodium caprinate and caprylate had a considerable, but smaller effect than oleic acid on the secretory plateau. Palmitate and laurate provoked only a slight decrease in acid secretion. Myristate was ineffective. These results could suggest that different receptors are responsible for fat-induced inhibition of the gastric acid secretion.