Effects of toxic doses of urethane on rat liver and lung microsomes

Administration of carcinogenic doses of urethane to male rats (for 30 days) and to females (for 45 days) caused degranulation of microsomes of livers and lungs to approx. 15 and 35%, respectively. The cholesterol levels also declined more than 50% in urethane-treated rats when compared with controls. Studies on structural components of microsomes have shown that urethane administration causes the depletion of phosphatidylinositol, phosphatidylcholine and phosphatidylethanolamine in microsomal preparations from lungs and livers with a concomitant loss of neutral lipids in lung microsomes. SDS gel electrophoresis has shown that with the administration of urethane, new proteins appeared in microsomal preparations from lungs whereas in livers disturbances in protein levels were observed.