ABSTRACT
The epithelium of the small intestine is a dynamic population of cells that are spatially segregated with respect to their degree of maturation. This chapter reviews the luminal cell surface components of the rat small intestine. Lectins are proteins or glycoproteins of nonimmune origin that have the ability to combine specifically with particular carbohydrate residues. Regions of the small intestine with different cell surface properties were relocated in an effort to determine whether luminal factors may play a role in determining the expression of the lectin receptors on cells lining the villi. Relocation was performed either by 70% proximal jejunoileal resection or by transposition of jejunal or ileal segments. Lectins have been used to characterize the luminal cell surface of the rat small intestinal epithelium. Fluorescence microscopy studies show that throughout most of the length of the small intestine the surfaces of the absorptive cells change as they migrate from the crypts to the villi.
