SMALL-INTESTINE ABSORPTION AND SECRETION

Major advances have occurred in the study of intestinal physiology and biochemistry. A microsomal triglyceride transport protein has been de scribed whose importance is highlighted in abetalipoproteinemics. Thes e patients do not synthesize microsomal triglyceride transport protein and cannot transport triglycerides, but they do produce beta lipoprot ein. Circulating fatty acids were shown to enter the intestine, become esterified to triglyceride, and enter a pool in which chylomicron for mation is selected against. Apolipoprotein A-IV was shown to be a phys iologically important satiety factor. Intestinal alkaline phosphatase was transfected into Caco-2 cells that produced a surfactant-like part icle. The ontology of complex lipid synthesis in Caco-2 cells as they matured at confluence was described. Aging was shown to be associated with a reduction in glucose transporters. Protein added to the diet wa s shown to increase peptidases at the level of transcription. A 14-kD protein appears to be important in intracellular bile-acid transport i n the ileum. Sensitized rats responded to oral rechallenge by the spec ific antigen with an increase in intestinal permeability.