[Coupling of protease activity and sodium loading with intestinal absorption of amino acids]

Membrane-bound serine proteases to play a certain role in activation of sodium transport in epithelial cells. To were found explain the protease activity and sodium-dependent L-tryptophan transport across chicken small intestine interaction, four experiments were conducted. One hundred chicks were fed diets that contained 0; 0.3; 3 or 6% of supplemental NaCl and were given distillated water ad libitum. Signs of salt toxicity observed were as follows: a decreased body weight, increased heart and kidney weights, formation of secondary lysosomes in enterocytes and lymphocytes. Such chickens were in the state of negative nitrogen balance. Intestinal absorption of L-tryptophan correlated with mucosal protease activity during increased dietary sodium chloride intake. Recent in vitro and in vivo experiments indicate that enterocyte proteases may be of critical importance in activation of sodium-dependent intestinal transporters for L-tryptophan.