Membranous and Soluble Forms of Intestinal Enzymes in Rat Pups, Whose Mothers Were Kept on a Low-Protein Diet during Pregnancy or Lactation

Activities of membranous and soluble forms of disaccharidases, alkaline phosphatase, and aminopeptidase M in jejunum and ileum was studied in the 10-, 20-, and 30-day old rat pups, whose mothers were kept at the period of pregnancy or lactation on a low-protein diet. The protein deficiency in mother's nutrition is shown to be accompanied by significant changes in the ratio of two forms of these membrane-bound enzymes. The greatest changes of this parameter are found for maltase, alkaline phosphatase, and aminopeptidase M in the 10-day old rat pups, while for lactase, in rat pups of all age groups. In some cases the maximal changes of the enzyme activity are revealed in rat pups, whose mothers were on the low-protein nutrition at the period of pregnancy (for example, saccharase), in other cases, in rat pups, whose mothers obtained such feeding during lactation (alkaline phosphatase), in the third ones, the changes were practically identical in the both groups of animals (maltase, while in some age groups, aminopeptidase M). The absence of changes in action of some modificators on activities of both forms of the studied enzymes allows suggesting that structure and properties of the studied enzyme proteins in the offspring's small intestine seem to remain unchanged under conditions of protein deficiency in mother's nutrition.