SUBCELLULAR CHARACTERIZATION OF GLYCOPROTEINS IN THE PRINCIPAL CELLS OF HUMAN GALLBLADDER - A LECTIN CYTOCHEMICAL STUDY

Citation
Jf. Madrid et al., SUBCELLULAR CHARACTERIZATION OF GLYCOPROTEINS IN THE PRINCIPAL CELLS OF HUMAN GALLBLADDER - A LECTIN CYTOCHEMICAL STUDY, Histochemistry, 101(3), 1994, pp. 195-204
Citations number
61
Categorie Soggetti
Cytology & Histology
Journal title
ISSN journal
03015564
Volume
101
Issue
3
Year of publication
1994
Pages
195 - 204
Database
ISI
SICI code
0301-5564(1994)101:3<195:SCOGIT>2.0.ZU;2-#
Abstract
Gallbladder mucus is mainly composed of glycoproteins, which seem to p lay a critical role in cholesterol nucleation during gallstone formati on. The biosynthetic pathway and sequential processing as well as the characterization of the oligosaccharide sidechains of human gallbladde r secretory glycoproteins have not been completely defined. The aim of the present study is the subcellular characterization of the glycopro teins in the principal cells of human gallbladder. Principal cells of normal human gallbladder were studied by means of a variety of cytoche mical techniques, including lectin histochemistry, enzyme and chemical treatments, immunocytochemistry and lectin-gold technology. Fucose, g alactose, N-acetylglucosamine, N-acetylgalactosamine and N-acetylneura minic acid residues were detected in mucous granules, Golgi apparatus and apical membrane of principal cells. Mannose residues were only obs erved in dense bodies. Oligosaccharide side-chains of the glycoprotein s contained in the biliary mucus are synthesized in the Golgi apparatu s of the principal cells of the gallbladder epithelium and are also co ntained in the mucous granules of these cells. Terminal N-acetylneuram inic acid(alpha 2-3)galactose(beta 1-3)N-acetylgalactosamine, N-acetyl neuraminic acid(alpha 2-3)galactose(beta 1-4)N-acetylglucosamine and g alactose(beta 1-4)N-acetylglucosamine sequences are contained in the o ligosaccharide chains of gallbladder mucus glycoproteins. The dense bo dies detected in the cytoplasm of the principal cells contained N-link ed glycoproteins. Mucin-type O-linked glycoproteins were the main comp onents of the mucous granules although some N-linked chains were also detected.