MICROFLORA MODULATES ENDOCRINE-CELLS IN THE GASTROINTESTINAL MUCOSA OF THE RAT

Background/Aims: Gastrointestinal peptides and biogenic monoamines par ticipate in the regulation of gastrointestinal functions. The aim of t his study was to examine the influence of the microflora on the distri bution of endocrine cells and on the release of gastrointestinal pepti des. Methods: A quantitative morphological study using stereological m ethods was performed in gastrointestinal sections of conventional and germfree rats. Tissue and plasma concentrations of peptides were measu red. Results: The total volumes of gastrin- and serotonin-immunoreacti ve cells were significantly increased in the gastric mucosa of germfre e rats (P < 0.05), as well as the total volumes of serotonin- and moti lin-immunoreactive cells in the ileum (P < 0.05) and serotonin-immunor eactive cells in the colonic mucosa (P < 0.05). The tissue concentrati on of somatostatin was significantly higher in the jejunum (P < 0.05) and lower in the ileum of germfree rats than in controls (P < 0.05). P lasma glucagon was significantly increased in germfree rats(P < 0.05). The total volume of the fundic mucosa was enlarged in germfree rats ( P < 0.05), whereas the total volume, the mucosal thickness, and the nu mber of crypt cells of the colonic mucosa were significantly reduced i n these rats compared with controls (P < 0.05). Conclusions: Our findi ngs suggest that the intraluminal microflora influences the release of biologically active peptides and that it participates in the regulati on of gastrointestinal endocrine cells and the epithelial structure.