Effect of a sunflower oil-supplemented diet on protein kinase activities of rat liver plasma membranes.

1. The effect of a sunflower oil-enriched diet on plasma membrane-bound protein kinase C, protein kinase A, casein and tyrosine kinase activities was studied. 2. The diet induced an increase in the content of linoleic acid and a decrease in the content of palmitic acid. The anisotropy parameter (rs) of the fluorescence probe DPH and SDPH decreased strongly in the experimental group. 3. Protein kinase C was stimulated more than two times. Tyrosine kinase, protein kinase A and casein kinase activities were increased by 65, 57 and 40%, respectively. 4. We suggest that a more fluid lipid environment favours higher plasma membrane-bound protein kinase activities.