Department of Biochemistry, Sri Krishnadevaraya University, Anantapur 515003, A. P., India
Received 4 August 2000; in revised form 5 June 2001; accepted 5 July 2001
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ABSTRACT |
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INTRODUCTION |
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MATERIALS AND METHODS |
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Sampling and assay methods
Blood samples were collected into EDTA-containing tubes by venepuncture and analysed immediately for plasma phospholipids and cholesterol by the methods of Connerty et al. (1961) and Zlatkis et al. (1953) repectively. Red cell preparation was according to the method described by Beutler (1975) and the extent of lipid peroxidation in red cells was measured by assaying malondialdehyde (MDA) formed according to the procedure of Buege and Aust (1978). Erythrocyte membrane preparations were obtained by the method of Dodge et al. (1963) and analysed for phospholipids and cholesterol (Jain et al., 1998). Membrane protein was assayed by the method of Lowry et al. (1951).
Chemicals
Thiobarbituric acid was obtained from Sigma Chemical Company, St Louis, MO, USA. All other chemicals were of analytical grade from Spectrochem Pvt. Ltd, Mumbai, India and Qualigens Fine Chemicals, Mumbai, India.
Statistical analysis
The data obtained in the present study were subjected to Duncan's multiple range test.
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RESULTS |
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DISCUSSION |
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The similar increases observed in the present study in the cholesterol contents of erythrocyte membranes of diabetics and alcoholic diabetics can be correlated to enhanced cholesterol levels in plasma in these two groups. There is evidence to indicate an accelerated transfer of cholesterol from plasma to erythrocyte membranes in many disease conditions, including diabetes, and also to ethanol consumption (Daniels and Goldstein, 1982). The decreased phospholipid content observed in alcoholic diabetic erythrocyte membranes seems to be independent of plasma phopholipids. However, a decrease in phospholipids has been reported in other membranes, such as hepatic (Cairns and Peters, 1983
), mitochondrial (Schilling and Reitz, 1980
) and erythrocyte membranes (Jain et al., 1988
) in non-diabetic alcoholics. The role of membrane-bound lipase in altering phospholipid composition in the alcoholic diabetics in the present study cannot be ruled out.
A marked decrease in C/P ratio in diabetic erythrocyte membranes was observed in the present study, which may indicate fluidization of membranes, which is in agreement with the report of Selvam and Anuradha (1988) in non- alcoholic diabetics. It is interesting to note that the increased C/P ratio in alcoholic diabetics indicates rigidification of membranes and the possibility of operation of a regulatory compensatory mechanism in chronic alcoholic diabetics to resist the fluidization of the membrane.
The observed increase in erythrocyte lipid peroxidation of diabetics is in agreement with an earlier report (Selvam and Anuradha, 1988). Ethanol-induced lipid peroxidation is well documented (Hrelia et al., 1986
; Gatti et al., 1993
; Morell et al., 1998
). The enhanced free radical generation by ethanol has been reported to be mediated by 2,3-butanediol and 1,2-propanediol, the two novel metabolites of alcohol in alcoholics (Xu et al., 1998
; Wei et al., 2000
). Although results from the present study indicate the beneficial effects of alcohol consumption by diabetics in bringing about an anti-fluidizing effect on membranes, further enhancement of lipid peroxidation in alcoholic diabetics suggests further damage to membrane organization and function.
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ACKNOWLEDGEMENTS |
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FOOTNOTES |
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REFERENCES |
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