RESUMO
In the intermediate area of the chicken stomach with A-avitaminosis the amount of the secretion increases and its chemical composition changes sharply: the content of water, lipids, hexolamines and suphates lowers. By means of 14-C-acetate, 35S-methionine and 35S-sulphate it is established that renewal of the secretion is inhibited. The electron-microscopic examinations showed that the secret is homogenous in normalcy but with A-avitaminosis it acquires a honeycomb structure, its physicochemical properties being changed: it becomes rigid, cuticle-like. As a result there appear deep cracks reaching mucosa, which lead to formation of erosions and ulcers. An assumption is advanced that the initial disturbances of the secretion might be not related to protein component (as the ratio of amino acids in it's almost unchanged) and depend on the carbohydrate and lipid components. The hypothesis of de Luc et al. as to the transport and intermediatory function of vitamin A in biosynthesis of glycosamineglycanes, glycolipids and glycolipoproteins is questioned. Vitamin A may take part in these processes but not as an intermediator of metabolic systems but as the level of biological structures (for instance, the Golgi apparatus and others) which organize these systems and coordinate their function.
