Regulation of fatty acid biosynthesis in Ehrlich cells by ascites tumor plasma lipoproteins

Richard McGee*, Douglas E. Brenneman, Arthur A. Spector

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Fatty acid biosynthesis in Ehrlich cells in vitro was reduced when very low density lipoproteins (VLDL) isolated from the ascites tumor plasma were added to the incubation medium. The degree of inhibition was dependent on the VLDL concentration. At the VLDL concentrations usually present in the ascites plasma, there was a 30% decrease in biosynthesis as measured by3H2O incorporation into fatty acids. Analysis of the labeled fatty acids by gas liquid chromatography indicated that this decrease was due to a reduction in fatty acid de novo biosynthesis and that chain elongation actually was increased when VLDL were present. Although ascites plasma low- and high density lipoproteins also produced a concentration-dependent inhibition of fatty acid biosynthesis, their effects were much smaller than those of the VLDL. Studies employing VLDL and radioactive free fatty acids indicated that the cells took up and utilized fatty acids derived from these lipoproteins. When VLDL were present, labeled free fatty acid incorporation into cell phospholipids, cholesteryl esters, and CO2 decreased, whereas its incorporation into the cell free fatty acid pool increased. By contrast, the cells incorporated only very small amounts of fatty acid from either low- or high density lipoproteins. This suggests that the VLDL exert their inhibitory effect on fatty acid synthesis by supplying exogenous fatty acids to the cells.

Original languageEnglish (US)
Pages (from-to)66-74
Number of pages9
JournalLipids
Volume12
Issue number1
DOIs
StatePublished - Jan 1 1977

ASJC Scopus subject areas

  • Biochemistry
  • Organic Chemistry
  • Cell Biology

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