The slowing of gastric emptying by proteins in test meals.

Abstract

SUMMARY1. Test solutions containing either glucose, casein, partially hydrolysed gelatin or egg albumin, native or denatured, at concentrations up to 50 g/l. in 33 mm-trisodium citrate solution, were given by tube into the stomachs of nine subjects in volumes of 600 or 750 ml.2. The volume of the test solution recovered from the stomach after 20 min was measured.3. The greater the concentration of solute the greater was the volume of the test solution recovered.4. Gram for gram, gelatin hydrolysate was equivalent to glucose in slowing gastric emptying. Casein was slightly more effective than glucose and native egg albumin was less effective than glucose.5. The results were explained by assuming that the products of hydrolysis of proteins stimulated osmoreceptors in the walls of the duodenum.6. The results were in line with the suggestion that proteins in food contribute to the slowing of gastric emptying in such a way that isocaloric amounts of carbohydrate and mixed protein have the same effect.7. There was a strong correlation between the concentration of glucose giving a recovery of 400 ml. and the corresponding concentration of casein within-subject, but there was no such relationship for gelatin hydrolysate. It was concluded that the between-subject variability in the digestion of casein was small, that for gelatin hydrolysate was large.

Stereospecific Effects of Intraduodenal Tryptophan on Pyloric and Duodenal Motility in Humans

“…Short-term intraduodenal infusions of glucose (13), fat (14), and acid (15) stimulate phasic pyloric pressure waves and basal pyloric pressure, suppress antral pressure waves, and probably delay gastric emptying through interaction with different receptors (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)34,35). There is evidence that the site and distribution of receptors vary for each nutrient (34,35) and that there are differences in receptor sensitivity within each nutrient class (2,16).…”

“…fats ( 2 . 14), and acid (3,15), and variations in receptor sensitivity and distribution have been identified within each nutrient class (2,9,16). The pylorus appears to play an important role in the regulation of gastric emptying of nutrient-containing liquids (17)(18)(19)(20)(21).…”

“…fat, acid. o r protein empty more slowly from the stomach than isotonic saline (1)(2)(3)(4). Studies of liquid gastric emptying in dogs (5)(6)(7).…”

Gastric Emptying in Prematures of Isocaloric Feedings with Differing Osmolalities

“…Fatty acids will also inhibit emptying although the chain length as well as concentration plays a major role with long chain fatty acids having a much greater inhibitory effect than medium chain fatty acids (16 protein will, in general, inhibit emptying to a degree consistent with the osmolality of the elemental components (5,8,15). If this situation applies during infancy one would expect no difference in emptying between the two feedings despite the difference in osmolality as the effective osmolality of hydrolyzed sucrose is the same as glucose.…”

Pepsin and Its Importance for Functional Dyspepsia: Relic, Regulator or Remedy?

“…Several contributing mechanisms can be distinguished: Osmotic effects, which are exerted by all amino acids alike [45,46], and additional pathways needed to explain more marked effects of phenylalanine [47] and especially tryptophan [35,48]. Around the same time, inhibition of gastric emptying was recognized as one of the physiological actions of CCK [49].…”