A COMPARISON OF MEMBRANE ENZYMES OF HUMAN AND PIG ESOPHAGUS - THE PIGESOPHAGUS GOOD MODEL FOR STUDIES OF THE GULLET IN MAN

The distribution and relative catalytic activities of five plasma memb rane enzymes (alkaline phosphatase, dipeptidyl peptidase IV, gamma-glu tamyl transpeptidase, microsomal alanyl aminopeptidase and glutamyl am inopeptidase) were examined in human and pig oesophagus. In both speci es, alkaline phosphatase activity occurred in basal and suprabasal cel ls of the epithelium and in capillaries. Stromal cells in the human su bmucosa were particularly reactive. Dipeptidyl peptidase IV was presen t in blood vessels and capillaries in man and pig and in submucous gla nds in the pig. The enzyme was also present in both species in the lam ina propria cells immediately adjacent to the epithelial basal lamina. In the human, gamma-glutamyl transpeptidase occurred in the epithelia l basal cells and in isolated basal and lower prickle cells in the pig . Stromal cells in the human submucosa were strongly reactive and capi llaries in the muscularis propria in both species moderately active. M icrosomal alanyl aminopeptidase was detected in lamina propria cells a djacent to the epithelial basal cell layer in man and pig and at the a pices of mucous cells in pig submucous glands. Weak glutamyl aminopept idase activity was confined to capillaries in both species. The findin gs of this study, along with the ready availability of pig oesophagus, suggest that the pig may be a suitable model for studies of the gulle t in man.