ENTEROKINASE AND INTRALUMINAL TRYPSIN ACTIVITY: DISTURBED RELATIONSHIP IN CHRONIC DIARRHEA IN CHILDREN

Abstract

Enterokinase initates digestion of protein by conversion of trypsinogen into trypsin. The possible failure of this function and the interactions between the two enzymes were investigated in two groups of infants with chronic diarrhea. The first group, included six infants (age 1 to 3 months) with intractable diarrhea of infancy, revealed reduced mucosal entnrokinase activity (9.5±6.5 μM/gP/min) and low intraluminal trypsin and enterokinase activities. After treatment with I.V. alimentation the activities of enzymes returned toward normal (enterokinase values = 49.6±17.5 μM/gp/min; normal values 91.0±43.2 μM/gP/min.). The mucosal morphology of all the pretreatment biopsies showed Grade III atrophy which improved to Grade I and II after treatment. The second group consisted of eight children (age 6 months to 4 years) with chronic nonsoecific diarrhea. Their intestinal mucosa demonstrated normal morphology and disaccharidase activities but decreased activity of enterokinase (10.4±3.8 μM/gp/min.) and intraluminal trypsin. These findings suggest that enterokinase deficiency and reduced trypsin in intractable diarrhea in infancy may be a contributing factor to the protein malabsorption and consequent malnutrition. The enterokinase deficiency in chronic nonspecific diarrhea has not been reported previously and may represent a new entity.