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.