Linolenic acid desaturation and chain elongation and rapid turnover of phospholipid n - 3 fatty acids in isolated rat liver cells.
The desaturation and chain elongation of [1-14C]linolenic acid was studied in isolated liver cells from rats fed a diet deficient in essential fatty acids. 14C-labelled 18:4, 20:3, 20:4, 20:5, 22:5 and 22:6, all n - 3 fatty acids, were formed. In the presence of lactate relatively large amounts of 20:5, 22:5 and 22:6 were formed. 20:5 was mainly present in phospholipids, 22:5 and 22:6 were present in both phospholipids and triacylglycerols. (+)-Decanoylcarnitine and (-)-hydroxycitrate decreased the formation of 20:5, 22:5 and 22:6 and increased the recovery of 18:4. The unchanged 18:3 substrate was also initially rapidly incorporated both in the phospholipids and in the triacylglycerol fraction. During long incubation periods, continued after nearly all the [14C]linolenic acid substrate had been metabolized either by esterification or by oxidation, the phospholipid content of labelled 18:3 and 18:4 decreased while the content of 20:5, 22:5 and 22:6 increased markedly, suggesting a remodeling of the phospholipid n - 3 fatty acid content by a series of deacylations-reacylations. The n - 3 fatty acid pattern in the triacylglycerol fraction changed little. 22:5 and 22:6 appeared in the VLDL fraction secreted by the isolated liver cells.
D000818:Animals; D004951:Esterification; D044943:Fatty Acid Desaturases / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism*; D066298:In Vitro Techniques; D008042:Linolenic Acids / Q000378:metabolism*; D008099:Liver / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D010084:Oxidation-Reduction; D010743:Phospholipids / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D005227:Fatty Acids; D008042:Linolenic Acids; D010743:Phospholipids; D044943:Fatty Acid Desaturases