Liver microsomal phospholipid fatty acids behavior and its relationship to bilirubin UDP-glucuronyltransferase activity in bile duct ligated rats.

Phospholipid fatty acid composition and bilirubin UDP-glucuronyltransferase activity from liver microsomal membrane were studied in normal and in bile duct ligated rats. Incubation of normal microsomes with 15 microM bilirubin (considered as physiological concentration) yielded 60% bilirubin diglucuronide; in 2 days post-cholestatic rats, they showed 20% bilirubin diglucuronide which was undetectable in 8 days post-cholestatic group. When compared to controls, after 2 days of cholestasis, microsomal phospholipids showed a clear decrease in linoleic and arachidonic acids and an increment in palmitic and stearic acids. 8 days post-cholestatic rats presented a marked increase in palmitic, oleic and docosaexaenoic acids, while linoleic and arachidonic acids decreased. Cholestasis produced disturbances in microsomal phospholipids fatty acid composition; but these changes are unable to explain entirely the severe damage observed in bilirubin diglucuronide formation.