Accumulation of neutral lipids by human skin fibroblasts: differential effects of saturated and unsaturated fatty acids.
The accumulation of neutral lipids by human skin fibroblasts grown in medium supplemented with fatty acids has been investigated. GM-10 cells incorporated exogenous fatty acids into both phospholipids and neutral lipids. More [14C]oleate, linoleate, or linolenate was incorporated into triacylglycerol than was [14C]palmitate or stearate. Supplementation of medium containing delipidized serum with unsaturated fatty acids resulted in far more stimulation of [14C]glycerol incorporation into triacylglycerol than did supplementation with saturated fatty acids. Palmitate- and stearate-fed cells incorporated sizable amounts of [14C] fatty acids and [14C]glycerol into diacylglycerol as well as triacylglycerol, especially at higher fatty acid concentrations. Increased oleate supplementation from 10-300 microM resulted in increased triacyglycerol synthesis and accumulation of discrete cytoplasmic lipid droplets; palmitate concentrations above 70 microgram were toxic. Micrographs of the palmitate-fed cells showed electron translucent slits, suggesting solid depositions of saturated fat, rather than the discrete osmiophilic droplets found in oleate-fed cells. Although GM-10 cells can synthesize fully saturated triacylglycerols, these data suggest that in cells fed saturated fatty acids, solid depositions of neutral lipids may sequester diacylglycerols and thus limit triacylglycerol synthesis.
D002460:Cell Line; D003470:Culture Media; D004075:Diglycerides / Q000096:biosynthesis; D005227:Fatty Acids / Q000378:metabolism*; D005230:Fatty Acids, Nonesterified / Q000494:pharmacology; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D008055:Lipids / Q000096:biosynthesis*; D011247:Pregnancy; D012867:Skin / Q000378:metabolism; D013329:Structure-Activity Relationship; D014280:Triglycerides / Q000096:biosynthesis
D003470:Culture Media; D004075:Diglycerides; D005227:Fatty Acids; D005230:Fatty Acids, Nonesterified; D005231:Fatty Acids, Unsaturated; D008055:Lipids; D014280:Triglycerides