Histamine and mast cell distribution in the intestinal wall of the germ free and conventional rats. Influence of the mode of sterilization of the diet.

The influence of the mode of sterilization of the diet (gamma-irradiation vs. autoclaving) on the histamine and mast cells distribution in the intestinal mucosa, was studied in germ free (GF) and conventional (CV) rats. Interactions between the diet and the digestive microflora were observed. Histamine concentration and mast cells counts are higher in CV rats small intestine than in GF's. The differences are increased with the irradiated diet. At the opposite in the hindgut, these values are higher in GF than in CV rats, especially in the rats fed the steam sterilized diet. The variations in the wall histamine contents and in the mucosal mast cells counts due to the diet and/or the microflora do not appear to be always correlated.