Pharmacological analysis of changes in the contentof diene conjugation, methyl esters of fatty acids of liver lipid fractions by cholinotropic agents during the overcooling of rats

The analysis of changes in the content of diene conjugation, fatty acid methyl esters (FAME) C20 of total lipids, fractions of free fatty acids (FFA) in the liver of animals exposed to overcooling for 3 hours and for 5 days after administration of cholinergic agents has been made. The obtained results indicate changing in the content of methyl esters of fatty acids and diene conjugation of FFA fractions after administration of pharmacological agents as neostigmine, pilocarpine, and atropine to animals on the background of cooling. Changes in the content of diene conjugation coincide with changes in the content of fatty acids (FA) C20 : 4 Δ-5,8,11,14 eicosatetraenoic acids (FA Arakhia) when pilocarpine or atropine was used. The presence of reciprocity was revealed. Basing the reciprocity factor, it was suggested that there was a possible effect of muscarine-sensitive structures of the plasmic membrane hepatocytes on the link between the content of FAME C20 Arakhia, phospholipase A2 activity and the change in the content of diene conjugation in fraction of liver FFA. A possible effect of cholinotropic agents on phospholipase A2 activity in the period of animal cooling was suggested.

Lipid fluidity of triacylglycerol-rich lipoproteins isolated from copper-deficient rats

Triacylglycerol-rich lipoproteins (TGRLP) were isolated from Cu-deficient and control rats. TGRLP from Cu-deficient rats appeared more fluid than those from controls as sensed by the fluorescence anisotropy of 1,6-diphenyl-l-3,5-hexatriene (DPH). This high fluidity was related to alow cholesterol: phospholipid ratio and high triacylglycerol content in these lipoproteins. TGRLP from Cu-deficient rats were more susceptible to in vitro peroxidation than lipoproteins from control rats as shown by the rate of diene conjugation. The damage induced by the peroxidation resulted in a more ordered state of the lipid fraction especially in lipoproteins from Cu-deficient rats. Thus, after in vitro peroxidation, TGRLP from Cu-deficient rats were more rigid than those from controls. These results suggest that Cu deficiency induces modifications in physicochemical properties of TGRLP which could affect their metabolism.