| Abstract: | Glycoconjugates associated with the basal cell layer of various types of epithelia in the mouse and rat were examined histochemically with a battery of lectin-horseradish peroxidase (HRP) conjugates of differing sugar binding specificities. Basal cells in paraffin sections of composite tissue blocks stained with an isolectin from Griffonia simplicifolia (GSA I-B4) specific for terminal alpha-galactose residues but failed to react with the other lectins. Basal cells in epithelium lining striated and excretory ducts of salivary and lacrimal glands, tongue, esophagus, trachea, renal calyx, ureter, urinary bladder, urethra, epididymis and vas deferens stained selectively and intensely for content of a glycoconjugate with terminal alpha-galactose. This galacto-conjugate appeared associated with the plasmalemma of basal cells. Basal cells with a galactocalyx formed an intermittent to continuous layer generally increasing in prevalence distally in glandular duct systems. A minor population of pyramido-columnar cells with cytosolic GSA I-B4 reactivity occurred in striated ducts and appeared less numerous in intralobular excretory ducts and more prevalent in extraglandular ducts. In trachea and renal pelvis, the GSA I-B4 positive cell profiles ranged from low cuboidal to tall pyramidal in contour, but the latter appeared not to reach the lumen. In contrast, no GSA I-B4 positive basal cells were seen in any segment of the pancreatic or bile ducts or in the epithelium of the gastrointestinal tract. These findings suggest that the basal cells found in similar sites in different epithelia and possessing in common a unique alpha-galactoconjugate may function in a manner common to all and not simply in providing progenitor cells for epithelial renewal.(ABSTRACT TRUNCATED AT 250 WORDS) |
