Phospholipid Metabolism of Liver Under Ischemic Hypoxic Condition

- Hepatic Artery Interrupted Dog -

Abstract

By interruption of hepatic artery in dogs, their livers were treated under the ischemic hypoxic condition and the chronological change of phospholipid in the liver cells was investigated pathobiochemically.
1) The hepatic artery interrupted dogs showed two different stages, in which one was severe liver dysfunction and the other was mild liver dysfunction according to clinical blood examination. In the case of the former dog group, GOT, GPT and IRG increased immediately and free amino acid in the plasma also increased after the interruption. In contrast, the ratio of BCAA to AAA decreased.
2) The sites of liver necrosis had dark purple color macroscopically and showed histologically the dilation of venous sinusoids and the marked atrophy with fatty degeneration of liver cells at central zone.
3) In the normal liver, there existed no regional difference in lipid and protein compositions. However, dog liver showed an individual difference in their compositions.
4) In the liver after hepatic artery interruption, phosp holipid which was main structural component in the cell membrane decreased drastically and total lipid and protein decreased moderately.
5) In the case with severe liver dysfunction, mitochondria and microsomes fractions showed the decreasing of phospholipid content but, in the case with mild liver dysfunction, mitochondria fraction showed no change of phospholipid content although microsomes fraction did the decreasing.
6) Thin layer chromatographic analysis of total lipid in the liver cells revealed that the phospholipid composition was unchanged and no accumulation of lysophospholipid was occurred, whereas free fatty acid increased after hepatic artery interruption.
7) Choline and ethanolamine glycerophospholipids were dominant in phospholipid of dog liver. In the constituent fatty acids of choline or ethanolamine glycerophospholipids, C_16:0: and C_18:2increased but C_20:4 decreased or C_16:0and C_18:2increased but C_22:6decreased, respectively, by hepatic artery interruption.
8) In the molec ular species of choline and ethanolamine glycerophospholipids, monoene and diene species, such as C_34:1, _34:2, C_36:1 and C_36:2, increased, while polyunsaturated species, such as C_38:4, C_38:5 and C_38:6 decreased by hepatic artery interruption. These results indicated that dysfunction of dog liver cells which was caused under the ischemic hypoxic condition might be related closedly with phospholipase function.