Lysosomal Enzymes in Human Fetal Gastrointestinal Tract

Abstract

Lysosomal Enzymes in Human Fetal Gastrointestinal Tract. Distribution and development of lysosomal enzymes (LE) in h unan fetuses have previously been studied only in small intestinal mucosa. In this study we examined for the first time the distribution and development of α - and β-glucosidase, α- and β galactosidase, N-acetyl-β-glucosaminidase, acid phosphatase and alk.phosphatase in gastric, duodenal,jejunal,ileal and colonic mucosa and lam.muscularis of 23 fetuses 12-36 weeks old.Enzyme activities were measured using a fluorometric method with methylumbiliferone coupled compounds as substrates. Activity was expressed as hydrolyzed substrate in nmoles/mg protein/min. At the 12th week of gestation in all parts of the G.I.tract LE activity could be detected. Activities were low in oesophageal,gastric and colonic mucosa;in jejunal and ileal mucosa they were tenfold increased (p<0.001);those found in lam.muscularis were similarily distributed.During gestation LE develop with lower activities in gastric,duodenal and colonic as they do in jejunal and ileal mucosa:we found a fivefold increasing activity from the 12thto 36thweek for α - and β-glucosidase,alkphosphatase and a sixfold decreasing activity in β-galactosidase and acid phosphatase. We conclude: 1)The topographical distribution of LE shows characteristic pattern with peak activities in small intestinal mucosa and lam.muscularis. 2)Lysosomal enzymes in the G.I.tract are already measurable at the 12thweek of gestation. 3)During gestation LE activities in gastric, duodenal and colonic mucosa develop similarily to those found in the small intestinal mucosa of human fetuses.