Sequential changes in lipid metabolism and the fatty acid profile in liver lipids during fasting and sepsis.

The sequential changes in lipid metabolism and in the fatty acid profile of liver lipids during fasting and sepsis were studied. Liver and blood specimens were taken from normally fed rats and from nonseptically and septically fasted rats at 5, 24, and 48 hr. Sepsis was induced by injecting live Escherichia coli bacteria intraperitoneally. Sepsis attenuated the fasting-induced increase in beta-hydroxybutyrate and reduced liver and serum triglycerides at 5 hr. There was a percentage decline in the most abundant fatty acids in neutral lipids, namely oleic (18:1w9) and linoleic (18:2w6) acids. This was seen throughout fasting and septic fasting. These results indicate that 18:1w9 and 18:2w6 are used as energy substrates and are oxidized to beta-hydroxybutyrate during fasting and mainly to carbon dioxide during septic fasting. On the contrary, the most abundant fatty acids in phospholipids, stearic (18:0), arachidonic (20:4w6), and docosahexaenoic (22:6w3) acids, accumulated in neutral lipids and in phospholipids throughout fasting. However, during sepsis this accumulation was reduced in neutral lipids and reversed to a level below that in the fed and fasted state in phospholipids. These results indicate that a disturbance in membrane integrity and function induced by septic fasting may have pathophysiological consequences for lipid metabolism and liver function during sepsis.