Small intestine cellular enzymes

Trypsin is typically considered an enzyme found in the pancreas and small intestine. However, trypsin, thrombin, and plasmin are also widely expressed in endothelium, including epithelial immune cells as well as neurons. Upregulated expression and release occurs during both acute and chronic inflammation [60], Autocrine release of trypsin and thrombin causes activation of protease-activated receptors (PARs) reaction leading to cellular proliferation and inflammation [4], This response includes release of proteins by all cells during chronic inflammation. Bik prevents PAR activation on cell surfaces. 

Neutral Gastrointestinal tissue Small intestine Colon Doses of 500 to 1,000 R cause degenerative changes within 30 minutes of exposure. Results of irradiation include impaired enzyme secretion, cellular degeneration and failure of absorption of nutrients, infection, dehydration from diarrhea. 

Drugs can cross the intestinal epithelial barrier in a number of ways. They may permeate either through the cell (transcellular) or between adjacent cells (para-cellular). Enterocytes have tight intercellular junctions that restrict paracellular transport to small hydrophilic molecules.7 These cells possess active and facilita-tive transporters for nutrients, as well as an array of efflux transporters [e.g., P-glycoprotein (P-gp) and related transporters] and enzymes (e.g., cytochrome P450 type 3A4) that restrict transcellular absorption. Transcytotic transport of macromolecules is possible, but compounds are often destroyed in lysosomes. With the exception of M-cells, transcytosis is not considered a major mechanism of the transcellular pathway for absorption of macromolecules across gastrointestinal epithelium.6... 

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