[Changes in the rat intestinal mucosa in hypervitaminosis A].

Administration of excess vitamin A to the growing male rats (50 000 IU of oily solution of retinol palmitate a day for 8 days) provoked a tendency toward a decrease in the number of goblet cells (of both absolute and relative number calculated per 500 cells of the epithelium) in the crypts and villi of the small intestinal mucosa, with this tendency being more marked in the inferior part of the intestine. At the same time administration of vitamin A excess increased the intensity of staining with alcyane blue of the secretion of the goblet cells, particularly on the apeces of the villi, which indicates the increased content of acid glycoconjugates in these cells. hypervitaminosis A was also accompanied by the intensification of infiltration with lymphocytes of the small intestinal epithelium and led to an increase in the number of plasma cells in the natural membrane of the villi. It is inferred that vitamin A excess produces an impairment in the program of enterocyte differentiation, characterized by both acceleration (an increase in the content of acid glycoconjugates in the goblet cells) and retardation (a decrease in the number of the goblet cells) of its individual aspects. At the same time hypervitaminosis A produces an adaptive-compensatory reaction on the part of the small intestinal mucosa, manifesting in activation of its infiltration with immunocompetent cells.