Subcellular distribution of phospholipids during liver damage induced by rare earths

After intravenous injection of praseodymium nitrate, female Wistar rats develop fatty livers. In contrast to the marked increase of triglycerides, the phospholipid content was only increased by 50%. The subcellular distribution of phospholipids showed that major changes occur in the microsomal fraction within the first 24 hrs. Among the individual phospholipids only phosphatidylcholine and phosphatidylethanolamine concentrations were elevated. Further subfractioning revealed that phospholipid concentration increased in the smooth endoplasmic reticulum, whereas it decreased in the rough endoplasmic reticulum. The individual phospholipids in the smooth endoplasmic reticulum increased to the same degree as did the total phospholipids. On the other hand, in the rough endoplasmic reticulum only the lecithin fraction decreased, while all other phospholipids remained unchanged. Cytochrome P450, cytochrome b5, and glucose 6-phosphatase activity were drastically reduced in the rough endoplasmic reticulum, while no changes could be observed in the smooth endoplasmic reticulum. In the serum, phospholipid concentration fell to half the normal value within the first 24 hrs after praseodymium intoxication.