Background. A direct relation has been found between the insulin sensitivity and fatty acid (FA) composition of serum and tissue lipids in adult humans. The aim of our study was to confirm the above relation in different groups of type 2 diabetic patients (DM2). Methods and Results. The FA composition of serum phospholipids was measured by gas liquid chromatography at the insulin action during the two-step hyperinsulinemic isoglycemic clamp (1 and 10 mU/kg.min) in a group of 21 netyly diagnosed DM2 subjects (DMN) and in 24 healthy controls (HC). The DMN group consisted of a subgroup of patients treated with hypoglycemic agents (DMH; n=21) and a group treated with the diet only (DMD; n=11). In diabetics, the metabolic clearance rates of glucose at either insulin level (MCRgwsubmax and MCRg,~max) were signi%cantly reduced in comparison with HS (MCRg,~submax - DMN: 5.35±2.7 ml.kg'.miri'; DMH: 5.38±2.17 ml.kg'.miri'; DMD: 5.48±2.35 ml.kg-'.min'; HS: 10.9±3.3 ml.kg'.min:'; ~<0.01; and MCRg,~max- DMN: 13.3±3.3 ml.kg'.miri'; DMH: 12.5±3.0 ml.kg'.miri'; DMD: 13.3±3.0 ml.kg-'.miri ; HS: 17.4±3.8 ml.kg'.miri'; p<0.05). An increased content of highly unsaturated n-6 family FA (p<0.01), especially of the arachidonic acid (DMN: 10.98±1.79 %; DMD: 10.78±1.64 %; DMH: 10.97±1.70 % vs HS: 8.51±1.53 % (p<0.01) was found in all groups of diabetics compared to HS, and lower levels of linoleic acid in DMN (p<0.001), and DMH (p<0.05) were identi%ed. The content of saturated FA and that of monosaturated FA was comparable in HS, DMN and DMD persons. While in healthy subjects a negative correlation between MCRg,~ and the content of saturated FA as well as a positive association between insulin action and the radon of linoleic and arachinonic acids were found, no such relation was found in the diabetic subjects. Conclusions. Different groups type 2 diabetic patients show altered FA pattern of serum phospholipids. Changes in FA composition may play a role in the modulation of insulin action in peripheral tissues, but they cannot explain the insulin resistance in type 2 diabetic patients.

        Key words: type 2 diabetes mellitus, insulin resistance, fatty acids, linoleic acid, arachidonic acid