title: Elevation of alkaline phosphatase by retinol in bovine endothelial cells and its possible relationship to lipid biosynthesis.
abstract: Alkaline phosphatase (EC 3.1.3.1) activity in bovine aortic endothelial cells in culture was stimulated in a synergistic manner by 10(-6) M retinol and by 10(-7) M dexamethasone. An early exposure to retinol was required for maximum stimulation and could be reproduced by the addition, during growth, of 2 micrograms/ml compactin. The induced enzyme activity in cell lysates prepared from cells treated with retinol and dexamethasone had a Vmax that was 50-fold that of the controls. The stimulatory effect of retinol could be partially reversed by the addition of sonic dispersions made from cholesterol and phosphatidylcholine. The incorporation of [14C]acetate into saponifiable and non-saponifiable cellular lipids was inhibited by 10(-6) M retinol but the activities of 3-hydroxy-3-methylglutaryl coenzyme A reductase (EC 1.1.1.34) and 3-hydroxy-3-methylglutaryl coenzyme A synthase (EC 4.1.3.5) remained unaffected. The results suggest that retinol might inhibit lipid biosynthesis through an alternate mechanism.
authors.forename: S E
authors.initials: SE
authors.lastname: Adams
authors.forename: E J
authors.initials: EJ
authors.lastname: Bishop
authors.forename: G
authors.initials: G
authors.lastname: Melnykovych
mesh_terms: D000469:Alkaline Phosphatase / Q000032:analysis*; D000818:Animals; D001011:Aorta / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D002784:Cholesterol / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology; D004357:Drug Synergism; D004727:Endothelium / Q000378:metabolism; D006903:Hydroxymethylglutaryl CoA Reductases / Q000032:analysis; D006904:Hydroxymethylglutaryl-CoA Synthase / Q000032:analysis; D008055:Lipids / Q000096:biosynthesis*; D008148:Lovastatin / Q000031:analogs & derivatives*; D009281:Naphthalenes / Q000494:pharmacology; D010713:Phosphatidylcholines / Q000494:pharmacology; D014415:Tunicamycin / Q000494:pharmacology; D014801:Vitamin A / Q000494:pharmacology*
chemical_list: D008055:Lipids; D009281:Naphthalenes; D010713:Phosphatidylcholines; D014415:Tunicamycin; D014801:Vitamin A; C012258:mevastatin; D003907:Dexamethasone; D002784:Cholesterol; D008148:Lovastatin; D006903:Hydroxymethylglutaryl CoA Reductases; D006904:Hydroxymethylglutaryl-CoA Synthase; D000469:Alkaline Phosphatase