In vitro and in vivo synthesis of long-chain fatty acids from (1-14C) acetate in the renal papillae of rats.
1. The relationship between the rate of [1-14C] acetate incorporation into the fatty acids of renal papillary lipids and the acetate concentration in the medium has been measured. 2. [1-14C] acetate was incorporated mainly into fatty acids of phospholipids and triacylglycerols. Only a few per cent of the radioactivity was found in the free fatty acid fraction. 3. The major part of the [1-14C] acetate was found to be incorporated by a chain elongation of prevalent fatty acids. The major component of the poly-unsaturated fatty acids in triacylglycerols and the major product of fatty acid synthesis from [1-14C] acetate in vitro was demonstrated by mass spectrometry to be docosa-7,10,13,16-tetraenoic acid. 4. The radioactivity of docosa-7,10,13,16-tetraenoic acid accounted for 40% of total radioactivity in triacylglycerol fatty acids (lipid droplet fraction) and 20% of total radioactivity in membrane phospholipid fatty acids.
D000818:Animals; D005227:Fatty Acids / Q000096:biosynthesis*; D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis; D008297:Male; D013058:Mass Spectrometry; D010743:Phospholipids / Q000096:biosynthesis; D051381:Rats; D014280:Triglycerides / Q000096:biosynthesis
D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D010743:Phospholipids; D014280:Triglycerides