Intestinal epithelium brush border and microsome chemistry. I. Crude cholera toxin effects.

Abstract

Abstract Sucrase, trehalase and aryl amidase are most probably located on the luminal surface of the intestinal microvilli, while sialic acids are found in glycoproteins in the glycocalyx and elsewhere on the cell surface. Phospholipids, cholesterol and glycolipids probably constitute the plasma membrane core. Exposure of the intestinal lumen surface to crude cholera toxin resulted in significant reductions in brush border and microsome sialic acids, phospholipids and cholesterol: protein ratios and brush border glycolipids: protein ratios. Cholera toxin had only minor effects on the three brush border enzymes. The toxin neuraminidase activity was insufficient to account for the observed effects on membrane sialic acids.