Partial characterization of a glycosylphosphatidyl-inositol (GPI) in porcine thyroid cultured cells.
The aim of this study was to provide information on the structure of glycosylphosphatidylinositol (GPI) and to characterize this novel phospholipid isolated from pig thyroid. We investigated the incorporation of different radioactive precursors: [3H]glucosamine, [3H]inositol, [3H]oleic acid, [32P]orthophosphate and demonstrated the presence of these moieties in the structure of GPI. After labelling and hydrochloric acid hydrolysis, the major part of radioactivity comigrated with glucosamine used as marker. Cleavage of GPI by nitrous acid deamination indicated the presence of a glycosidic bond between the lipid moiety and glucosamine. The fatty acid composition of diacylglycerol was also studied by gas chromatography. Oleic acid was found preferentially to other fatty acids. In a previous paper we reported that a chronic treatment with 0.1 mU/ml thyrotropin (TSH) of thyroid cultured cells for 3 days produced a large increase in the turnover rate of GPI and concomitantly the release of a water-soluble product of GPI hydrolysis: an inositolphosphateglycan (IPG). These findings confirm that GPI may play a role in membrane signalling systems and thyroid cell regulation.
Université de Reims Champagne Ardenne, Laboratoire de Biochimie, UFR Sciences de Reims ERS-CNRS 0017, France.
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Petitfrere
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Aguie-Aguie
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Sartelet
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Martiny
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Haye
D000818:Animals; D002478:Cells, Cultured; D002849:Chromatography, Gas; D005944:Glucosamine / Q000378:metabolism; D017261:Glycosylphosphatidylinositols / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D006851:Hydrochloric Acid; D007294:Inositol / Q000378:metabolism; D009608:Nitrous Acid; D019301:Oleic Acid; D009829:Oleic Acids / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism; D010716:Phosphatidylinositols / Q000378:metabolism; D013552:Swine; D013961:Thyroid Gland / Q000737:chemistry*; D014316:Tritium
D017261:Glycosylphosphatidylinositols; D009829:Oleic Acids; D010710:Phosphates; D010716:Phosphatidylinositols; D014316:Tritium; D019301:Oleic Acid; D007294:Inositol; D005944:Glucosamine; D006851:Hydrochloric Acid; D009608:Nitrous Acid