Frozen myocardium was ground to powder and H-myocardial lipids were extracted with chloroform :methanol (Folch). After washing, the lipids were re-solubilised in chloroform and separated by TLC using a hexane-diethylether-acetic acid system. Lipid classes were counted for 3H-radioactivity.

2.5. Lipoprotein Lipase Activity

Myocardial LPL activity was estimated in post-heparin perfusate ("heparin-releasable") and in acetone/ether-dried ground tissue powders ("residual-tissue") by using a 3H-labelled triolein substrate emulsion and counting radioactivity in evolved fatty acids extracted in methanol/chloroform/heptane.5

2.6. Analysis of VLDL Composition

Apoprotein composition was analysed by denaturing SDS-polyacrylamide gel electrophoresis/Coomassie Brilliant Blue staining and densitometry; lipid composition (NEFA, TAG, cholesterol and cholesterol ester, and phospholipid) was determined with commercial kits (Sigma).

2.7. Statistics

Results are expressed as mean values ± SEM. Statistical analysis was performed by one-way analysis of variance (ANOVA) for repeated measurements, or by Student's t test with Bonferroni correction for multiple comparisons, where appropriate. Statistical significance was set at P < 0.05.

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