Mitochondrial changes in phospholipid molecular species during the increased oxidative phosphorylation after...

The changes in liver mitochondrial and microsomal phospholipid molecular species were analyzed during the period of remarkably increased oxidative phosphorylation following partial hepatectomy in rabbits. At 24 hours after hepatectomy, phosphorylative activity increased significantly from 69.7 +/- 5.5 to 118.5 +/- 5.7 nmol of ATP synthesized/min/mg protein, compared to the sham operated group. The ratio of phosphatidylethanolamine to phosphatidylcholine (PE/PC) in mitochondria increased significantly in the hepatectomy group compared with the sham operated group. Remarkable changes in molecular species were observed in mitochondrial phosphatidylethanolamine. 1-Stearoyl-2-arachidonoyl species decreased in the hepatectomy group. On the other hand, microsomal phospholipids hardly changed compared with mitochondrial ones. The change in content of 1-stearoyl-2-arachidonyl phosphatidylethanolamine in mitochondria tended to return to normal levels concomitant with the normalization of phosphorylative activity. The changes in content of mitochondrial phospholipids, especially phosphatidylethanolamine, might also be related to enhancement of phosphorylative activity.