Identification of bitter-taste intensity and molecular weight as amino acid determinants for the stimulating mechanisms of gastric acid secretion in human parietal cells in culture.

Secretion of gastric acid, aimed at preventing bacterial growth and aiding the digestion of foods in the stomach, is chiefly stimulated by dietary intake of protein and amino acids (AAs). However, AAs' key structural determinants responsible for their effects on mechanisms regulating gastric acid secretion (GAS) have not been identified yet. In this study, AAs have been tested in the parietal cell model HGT-1 on GAS and on mRNA expression of genes regulating GAS. AAs' taste intensities from 0 (not bitter at all) to 10 (very bitter) were assessed in a sensory study, in which ARG (L: 6.42 +/- 0.41; D: 4.62 +/- 0.59) and ILE (L: 4.21 +/- 0.43; D: 2.28 +/- 0.33) were identified as bitter-tasting candidates in both isomeric forms. Pearson correlation showed that GAS in HGT-1 cells is directly associated with the bitter taste quality (r: -0.654) in combination with the molecular weight of L-AA (r: -0.685).