Mechanisms of carbon tetrachloride hepatotoxicity.

CCI4 has long served as a model compound for study of hepatotoxicity. While its simple chemical structure held the allure of a simple mechanism of action, decades of study have disclosed a complex series of responses. Significant early damage following CCI4 administration includes: (1) A number of alterations affecting Ca2+ homeostasis, which conspire to redistribute cellular Ca2+ from endoplasmic reticulum and mitochondria to cytosol, and (2) hypomethylation of ribosomal RNA, which disrupts protein synthesis. The genesis of the injury in vivo appears to encompass early 'metabolism-dependent' effects (which appear to be largely independent of CCI4 concentration at the levels studied) and later 'metabolism-independent' effects, which parallel CCI4 concentration. The inability of injured hepatocytes to respond anabolically to early damage may be a critical feature in CCI4 hepatotoxicity.