Abstract
The mechanism by which polyenoic acids control the amount and positioning of monounsaturated fatty acids in choline phosphoglycerides from baby hamster kidney cells was studied. Under normal growth conditions monoenoic acids were derived from the desaturation of saturated fatty acids and comprised over 50% of the fatty acids at position 1 of the glycerol moiety. The monoene content of positions 1 and 2 decreased in response to the addition of di- and polyenoic acids to the culture medium. All the di- and polyenoic acid supplements tested inhibited the desaturation of palmitic and stearic acid and replaced monoenes at position 2. However only linoleic, linolenic, and eicosadienoic acids replaced monoenes at position 1. The results suggest that under appropriate conditions up to 25% of the choline phosphoglyceride fraction consisted of a stable molecular species containing di- or trienoic fatty acids at both the 1 and 2 positions of glycerol moiety. With eicosatrienoic or arachidonic acid supplements, on the other hand, the monoenes at position 1 were replaced with saturated fatty acids. The magnitude of these effects, particularly at position 1, was proportional to the concentration of the fatty acid supplement. The results suggest that polyenes with at least 20 carbon atoms can play a key role in determining the ultimate composition and positioning of fatty acids in baby hamster kidney choline phosphoglycerides and that this control is mediated by their ability to inhibit delta 9 desaturase and by a retailoring system specific for these polyenes.
Highlights
Response to the addition of di- and polyenoic acids to most studies with isolated microsomes have shown theculture medium
The results suggest that polyenes with a t least 20 lethanolamine in aging hepatocyte cultures increases as the carbon atoms can play a key role in determining the polyenoic acid content of total cellular lipids decreases (1).In ultimate composition and positioning of fatty acids in the livers of animals fed an essential fatty acid-deficient diet baby hamster kidney choline phosphoglycerides and that this controlis mediated by their ability to inhibit A 9 desaturase andby a retailoring system specificfor these polyenes
Influence of Fatty Acid Supplements on thCeomposition and Positioning of Fatty Acids in Phosphatidylcholine-Nearly 50%of the total fattyacids in phosphatidylcholine from BHK cells consists of monoenoic acids, 18:1 (l).'Since this findingis reminiscent of that seen in tissues from essentialfatty acid-deficient animals (15), the effect of supplementing the growth medium with saturated and unsaturated fatty acids on the composition and distribution of fatty acids in phosphatidylcholine from BHK cells was examined
Summary
Media-The designations are: A, minimum essential medium (16) with Earle’s salts; B, A supplemented with 10% fetalcalf serum; and C, B supplemented with 0.5% glucose. Phospholipids, except phosphatidic acid, wereresolvedby thin layer chromatography of 10-pl aliquots on Silica Gel H-coated plates using chloroform/acetic acid/water (100:60:16:7, v/v) to develop the plates (1). Lipid extracts of the cells were resolved into diacyland triacylglycerol, fatty acids, and phospholipids by thin layer chromatography using hexane/ether/acetic acid (7030:1, v/v). The distribution of radioactivity among the various lipid classes was determined by scraping the appropriate section of the silica gel plate into counting vials containing 0.3 mlof H20.After the addition of scintillation fluid, the samples were counted. The distribution of radioactivity between the two hydrolysis products was determined by subjecting a IO-pl aliquot to thin layer chromatography using chloroform/methanol/water (65:25:4, v/v) as the developing solvent. The silica gel scrapings were used to prepare the fatty acid methyl esters by the procedure employed previously (1). All other materials and chemicals were obtained as described previously (1)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
