Intestinal release of mucin in response to HCl and taurocholate: Effect of indomethacin

1. 1. Alkaline secretion and mucin output were analyzed along the gastrointestinal tract of a dog in response to luminal application of HC1 and taurocholate with and without pretreatment with indomethacin. 2. 2. Mucins derived from the different areas displayed similar contents of protein and carbohydrate but differed with respect to associated and covalently bound lipids. 3. 3. Application of HC1 or taurocholate in all the regions caused an increase in the output of mucins and HCO₃^-. However, mucins elaborated in response to HC1 exhibited higher total lipid content and were richer in phospholipids. 4. 4. Pretreatment with indomethacin prior to HC1 application led to a reduction in HCO₃^- and caused a decrease in mucin phospholipid content, but had no effect on HCO₃^- secretion and the lipid content of mucins elaborated in response to taurocholate. 5. 5. The results indicate that mucins elaborated along the gastrointestinal tract differ with respect to lipids, and that their output in response to HC1 is mediated by prostaglandins.