Abstract

Alteration in the cytoplasmic, mitochondrial and peroxisomal membrane phospholipid has been investigated in 31- diamino-azo-benzene (DAB) -induced hepatocellular carcinoma in rats. The cytoplasmic membrane of tumour group shows 27.5, 19.7, 38.7 and 34.7% increase in phosphatidylserine, phosphatidylcholine, phosphatidylethanolamine, and sphingomyelin respectively compared with the control group, mitochondrial membrane shows 46.4, 67.2, 64, and 73.4% decrease in phosphatidylserine, phosphatidylcholine, phosphatidyletholamine, and sphingomyelin respectively in tumour group compared with the control. Peroxisomal membrane phosphatidylserine, phosphatidylcholine, phosphatidylethanolamine and sphingomyelin composition of the tumour decreased by 20.0, 44.4, 79.2 and 78.6% compared with the control. The altered phospholipid is associated with altered cellular enzyme distribution. The soluble fraction of the cytoplasm shows specific activities of catalase and D-amino acid oxidase in soluble fraction of tumour group are 23.3 and 23.0% lower respectively compared to that of the control while Succinate dehydrogenase in tumour group is 42.2% higher than control group, the mitochondrial fraction shows specific activities of catalase, Succinate dehydrogenase and D-amino acid oxidase are 33.3, 33.3, and 58.3% higher respectively in control than the tumour group. The specific activities of catalase, Succinate dehydrogenase and D-amino acid oxidase are 61.5, 50.3, and 56.7% higher respectively in control compared with the tumour group. In the cytoplasmic, mitochondrial and the peroxisomal fractions of the control group, the phospholipid/protein ratio increased by 18.8, 35.7 and 48.6% respectively above the tumour group. These alterations might have implications on the metabolism, functions, morphology, metastasis and apoptosis in transformed cells.

Key words: Tumour, phospholipids, enzymes, phospholipid/protein ratio.