The effect of adjuvant-induced arthritis on rat liver microsomal phospholipid metabolism

Rats given a single subdermal injection into the left hind paw of 0.5 mg Mycobacterium tuberculosis suspended in 0.1 ml of mineral oil, after several days of latency, developed arthritis accompanied by depression in liver microsomal phosphatidylcholine and phosphatidylethanolamine synthesis at 7, 14 and 21 days. The depression of liver microsomal phosphatidylcholine and phosphatidylethanolamine concentrations of experimental animals was accompanied by decreased incorporation of radioactive palmitate into both phospholipids. Nevertheless, the biosynthesis of phosphatidylcholine via the methylation pathway was unaffected. These observations suggest that adjuvant arthritis affects quantitatively the phospholipid composition of the liver endoplasmic reticulum, which consequently may lead to impairment of the microsomal drug-metabolizing enzyme system.