title: Efflux of sphingolipids metabolically labeled with [1-3H]sphingosine, L-[3- 3H]serine and [9,10- 3H]palmitic acid from normal cells in culture.
abstract: The membrane complex lipids of human fibroblasts and differentiated rat cerebellar granule cells in culture were metabolically radiolabeled with [1-(3)H]sphingosine, L-[3-(3)H]serine and [9,10-(3)H]palmitic acid. A relevant efflux of radioactive sphingolipids and phosphatidylcholine was observed from cells to the culture medium in the presence of fetal calf serum. This event was independent of the concentration and structure of the metabolic precursor administered to cells, and it was linearly time-dependent. The radioactive lipid patterns present in the medium were different from those present in the cells. Radioactive sphingomyelin and ganglioside GM3 containing short acyl chains were the main species present in the medium from human fibroblasts, while sphingomyelin and GD3 ganglioside in that from neuronal cells. In the absence of proteins in the culture medium, the efflux of complex lipids was much lower than in the presence of serum, and the patterns of released molecules were again different from those of cells.
authors.affiliation: Center of Excellence on Neurodegenerative Diseases, Department of Medical Chemistry, Biochemistry and Biotechnology, University of Milan, 20090, Segrate, Italy.
authors.forename: Vanna
authors.initials: V
authors.lastname: Chigorno
authors.forename: Mariateresa
authors.initials: M
authors.lastname: Sciannamblo
authors.forename: Joanna
authors.initials: J
authors.lastname: Mikulak
authors.forename: Alessandro
authors.initials: A
authors.lastname: Prinetti
authors.forename: Sandro
authors.initials: S
authors.lastname: Sonnino
mesh_terms: D000818:Animals; D002240:Carbohydrate Sequence; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology; D003470:Culture Media / Q000494:pharmacology; D005347:Fibroblasts / Q000378:metabolism; D005679:G(M3) Ganglioside / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D019308:Palmitic Acid / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D010713:Phosphatidylcholines / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values; D012694:Serine / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D013107:Sphingolipids / Q000378:metabolism*; D013109:Sphingomyelins / Q000378:metabolism; D013110:Sphingosine / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D014316:Tritium
chemical_list: D003470:Culture Media; D005679:G(M3) Ganglioside; D010713:Phosphatidylcholines; D013107:Sphingolipids; D013109:Sphingomyelins; D014316:Tritium; D019308:Palmitic Acid; D012694:Serine; D013110:Sphingosine