[Proteolytic activity of the rat stomach in early ontogenesis during artificial feeding with milk substitutes]

Artificial feeding of new born rats, using milk substitutes containing proteins of rat and cow milk, led to 2-5-fold increase in the total proteolytic activity of stomach contents. In this case proteinases exhibiting pH optima at highly acidic pH were mainly activated. Proteolytic activity exhibiting an optimum at pH 8.0 was found in stomach contents of all the animals studied but it was the most distinct in the experimental group. By means of gel filtration the low molecular products of proteolysis were found in stomach contents; their concentration was 2-fold higher in the new born rats maintained on a diet including cow milk proteins.