Effects of bleomycin and methylprednisolone on the biosynthesis of oligosaccharide-lipids and glycoproteins in lung.
Tissues from rabbit lung were found to incorporate radioactivity from [3H]mannose into the oligosaccharide of a polar lipid soluble in chloroform/methanol/water (10:10:3, by vol.). Only one oligosaccharide-lipid was formed and the composition of the radiolabelled carbohydrate moiety was Glc3Man9(GlcNAc)2. An antitumour antibiotic, bleomycin, and an anti-inflammatory steroid, methylprednisolone, partially inhibited the incorporation of [3H]mannose into oligosaccharide-lipids and in addition resulted in the production of two new components, Man5(GlcNAc)2 and Man2(GlcNAc)2. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of the glycoproteins synthesized from the oligosaccharide-lipid intermediates showed labelled components with Mr greater than 200000, 130000, 80000 and 62000. The addition of the drugs resulted in the same pattern with the addition of a new component of Mr 36000. Endoglucosaminidase H-treatment of the glycopeptides isolated from the Pronase-digested glycoproteins indicated that the oligosaccharide units in the glycoproteins were of the high-mannose-type.
D000818:Animals; D001761:Bleomycin / Q000494:pharmacology*; D002850:Chromatography, Gel; D004305:Dose-Response Relationship, Drug; D006023:Glycoproteins / Q000096:biosynthesis*; D066298:In Vitro Techniques; D008070:Lipopolysaccharides / Q000096:biosynthesis*; D008168:Lung / Q000187:drug effects / Q000378:metabolism*; D008358:Mannose / Q000378:metabolism; D008775:Methylprednisolone / Q000494:pharmacology*; D014176:Protein Biosynthesis; D011817:Rabbits
D006023:Glycoproteins; D008070:Lipopolysaccharides; C023023:lipid-linked oligosaccharides; D001761:Bleomycin; D008358:Mannose; D008775:Methylprednisolone