Biosynthesis of intestinal mucins. 1. Survey of incorporation of [35S]sulphate by isolated gastrointestinal tissues

Abstract

The O2 uptake and incorporation of (S35) sulfate by isolated tissues of the gastrointestinal tract of several animals were measured. Incorporation of S35 sulfate by gastric mucosa of sheep, calf, frog and guinea pig was negligible (less than 2 counts/mg of dry tissue); uptake by lower regions of sheep and guinea pig intestine, especially by colon, was considerable (10-60 counts/mg of dry tissue). Penetration of gastric and colonic tissue by S35 sulfate was determined and found to be similar for these 2 tissues (approximately 60%). The ester sulfate and amino sugar contents of gastric and colonic mucins were measured. Differences in incorporation of S35 sulfate by gastric and colonic tissue were not accounted for on the basis of (a) penetration of S35 sulfate into the tissue or (b) the degree of sulfation of the mucins produced by the tissue. The blood-group specificity of several types of gastrointestinal mucin was determined: activity was restricted to mucins isolated from gastric tissue.