Regulation of polyunsaturated fatty acid biosynthesis in the rat
Sprecher, H.W.
Federation Proceedings 31(5): 1451-1457
1972
ISSN/ISBN: 0014-9446 PMID: 5056171 Document Number: 50929
Although it is firmly established that linoleate, linolenate, oleate and palmitoleate each serve as the initial unsaturated precursor for an independent family of polyunsaturated fatty acids, little is known about the mechanisms which regulate polyunsaturated fatty acid biosynthesis. When rats are on a balanced diet, the tissue lipids do not contain polyunsaturated fatty acids derived from palmitoleate or oleate. Conversely when rats are deprived of essential fatty acids the tissue lipids contain a high level of 20:3 omega 9, which is an acid derived from oleate. Tissue lipids of these animals also contain small amounts of 20:3 omega 7 and 20:3 omega 7 which are derived from palmitoleate. Feeding studies and isotope studies in vitro coupled with enzymic studies suggest that the intermediates in the palmitoleate pathway do not serve as efficiently for the biosynthesis of omega acids as do the omega 6 metabolites for the biosynthesis of analogous omega 6 acids. Competitive interactions between omega 6 and omega 9 acids relative to desaturation as well as individual rates of conversion within the omega 9 pathway regulate the biosynthesis of omega 9 polyunsaturated fatty acid in the rat.