Release of Enzymes from Rat Jejunal Mucosa by Bile Salts

Sununary: The technique of segmental perfusion was applied in vivo to study the release of enzymes from the mucosa cells under the influence of bile salts. Five brush border membrane enzymes, five cytosolic, one mitochondrial and two lysosomal enzymes were measured. Spontaneous release (Ringer solution), due to their superficial localization, was greatest for enteropeptidase and a-glucosidase. 3 and 10 mmol/1 sodium taurocholate, and 0.5 and 3.0 mmol/1 chenodeoxycholate were used. Surprisingly, the majority of cytosolic enzymes was released to a greater extent than membrane enzymes. On the other band, lysosomal or mito-chondrial enzymes were low or absent in the perfusion medium, a finding that excludes a serious injury to the mucosa cells. It must be inferred, therefore, that cytosolic enzymes are regularly externalized during the digestive process, the glycocalyx perhaps being a common matrix for pancreatic, membrane-associated and cytosolic enzymes. Freisetzung von Enzymen aus der Jejunumschleimhaut der Ratte durch Gallensalze Zusammenfassung: Um die Freisetzung von Enzymen aus den Mucosazellen unter dem Einfluß von Gallen-salzen zu untersuchen, wurde die Technik der segmentalen Perfusion angewendet. Es wurden 5 Bürstensaum-membranenzyme, 5 cytosolische, l mitochondriales und 2 lysosomale Enzyme bestimmt. Die spontane Frei-setzung (Ringer^Lösung) war wegen ihrer oberflächlichen Lokalisierung am stärksten bei Enteropeptidase und-Glucosidase. Bei den eingesetzten Gallensalzen handelte es sich um 3 und 10 mmol/1 Natriumtauro-cholat und 0,5 und 3,0 mmol/1 Chenodesoxycholat. Überraschenderweise wurde die Mehrzahl der cytosoli