Liver lipid response to intravenous rare earths in rats

Abstract

Intravenous injection of rare earths with low atomic numbers produces fatty infiltration in the liver of rats. This infiltration is maximal 48 hours later and is characterized by an increase in neutral fat esters. Total cholesterol and phospholipids of the liver in cerium-treated rats were similar to those of control livers. Cerium was found to be effective in producing extremely high levels of liver fat in female rats of several strains tested. Male rats treated in the same way did not exhibit the consistent response or the high liver-lipid levels that were seen in the females. After the castration of male rats, their response resembled that of females. Testosterone caused a significant reduction in the fatty infiitration induced by cerium in both intact and ovariectomized females. Hypophysectomy prevented fatty livers in both females and males, whereas adrenalectomy did so only in males. Choline and methionine had no protective effect against cerium. Tracer experiments involving cerium144 demonstrated that most of the radioactivity appeared in the acid-soluble fraction of the liver and that the lipid fraction contained essentially no tracer.