[Studies on the value of fecal tryptic and chymotryptic activity in the diagnosis and therapy of cystic fibrosis (author's transl)].

Under certain conditions the determination of the tryptic activity, especially of the chymotryptic activity in the feces mostly of infants in the first 4-6 weeks of life is considered to be an important step in the diagnosis of cystic fibrosis. The tryptic anc chymotryptic activity in the feces of children with cystic fibrosis declines when the substitution of pancreatic enzymes is stopped. On resubstitution, the activity rises in relation to the dose and attains the activity related to age as found in healthy children. A comparison of the proteolytic activity with the fat content of the feces during the study period without the enzyme substitution and during the period when the enzyme dosage varied showed no significant correlation. It is not possible to postulate a poor excretion of fats merely from the high proteolytic activity of the feces because the fecal proteolytic activity and the fat excretion are not inversely proportional to one another. For this reason, one cannot conclude that the grade of the proteolytic activity in the feces of patients with cystic fibrosis is a yardstick for the total digestive process when they are under pancreatic enzyme substitution.