Predominance of the acylation route in the metabolic processing of exogenous sphingosine in neural and extraneural cells in culture

Laura Riboni, Rosaria Bassi, Alessandro Prinetti, Paola Viani, Guido Tettamanti

Research output: Contribution to journalArticle

Abstract

The metabolic fate of exogenous [3H]sphingosine was investigated in five types of cultured cells: primary cultures of neurons and astrocytes, murine and human neuroblastoma cells and human skin fibroblasts. After administration of 40 nM [3-3H]sphingosine into a cell-conditioned medium containing fetal calf serum, all cell types rapidly and efficiently incorporated the long-chain base in a time-dependent fashion. In all cases, after a 120 min pulse, the amount of radioactivity taken up was in the range of the endogenous sphingosine content. However, unchanged [3H]-sphingosine represented only a very minor portion of the label incorporated into cells throughout the pulse period (10-120 min), indicating rapid and efficient sphingosine metabolism in these cells. Most of the [3H]sphingosine taken up was metabolically processed, either by degradation (assessed as 3H2O release into the culture medium) or by N-acylation (mainly to radioactive ceramide, sphingomyelin, neutral glycolipids and gangliosides). [3H]Sphingosine 1-phosphate accounted for less than 2% of the total radioactivity incorporated in all cases. Throughout the pulse period and in all cell types. 3H-labelled organic metabolites largely prevailed over 3H2O, indicating that N-acylation is the major metabolic fate of sphingosine in these cells under apparently physiological conditions. These results are consistent with the notion that sphingosine has a rapid turnover in the cells studied, and indicate that regulation of the basal level of this bioactive molecule occurs mainly through N-acylation.

Original languageEnglish
Pages (from-to)147-151
Number of pages5
JournalBiochemical Journal
Volume338
Issue number1
DOIs
Publication statusPublished - Feb 15 1999

Keywords

  • Ceramide
  • N-acylation
  • Sphingosine metabolism

ASJC Scopus subject areas

  • Biochemistry

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