Effect of unilateral ureteral obstruction on metabolism of renal lipids in the rat.

The metabolism of lipids in the cortex and inner medulla of control and experimental kidneys of rats with unilateral ureteral obstruction (UUO) was studied in vitro. A marked increase in the tissue triglyceride content was noted after 24 h of obstruction in the experimental kidney compared with the contralateral kidney of rats with UUO and normal kidneys from sham-operated rats. A decrease in total phospholipid content was seen in the experimental kidney after 24 h of obstruction. The incorporation of [1-14C]oleic acid or [14C]arachidonic acid into tissue triglycerides was significantly increased in the cortex and medulla of the experimental kidney of rats with UUO compared with either the contralateral kidney of the same animals or kidneys from sham-operated rats. The oxidation of [1-14C]oleic acid to 14CO2 and the incorporation of [14C]arachidonic acid into tissue phospholipids or free fatty acids were significantly lower in the experimental kidney of rats with UUO. The results strongly suggest an increase in the net synthetic rate of triglycerides in the experimental kidney of UUO rats. This increase may be related to both a decrease in fatty acid oxidation and an increased release of fatty acids from phospholipids presumably due to increased phospholipase activity.