Perivenous zone

Hepatocytes display metabolic heterogeneity according to their zonal location within the acinus. (42) (s. p. 24) Specific chemical processes thus proceed exclusively or predominantly in the hepatocytes of the periportal or the perivenous zones. The zonally segregated reactions may also be regulated separately. It seems that, under certain conditions, metabolic processes are also shifted from one zone of the acinus to another. 

Periportal zone (zone 1) Perivenous zone (zone 3) ... 

In the course of cholestasis, lower concentrations of cytochrome P 450 are found together with increased activities of some microsomal oxidases. For this reason, the biotransformation of xenobiotics can be unpredictably and permanently altered. This is largely connected with the cholestasis-associated shift in bile acids from the periportal to the intermediary and perivenous zones. 

The regional expression of xenobiotic metabolizing enzymes determines the zone-specific localization of toxicant damage. Many hepatotoxicants elicit perivenous damage because CYPs are preferentially localized in centrilobular hepatocytes. For example, acetaminophen causes hepatotoxicity because the reactive... 

Fig. 2.15 Diagram of the liver lobule and the acinus arranged like a clover leaf around the portal field according to the acinar structure (modified from D. Sasse, t986) central hepatic vein (CV) or terminal hepatic vein, periportal field (P). Circulatory and meta-bolically different zones zone t (periportal), zone 2 (intermediate), zone 3 (perivenous)...

Alcoholic hepatitis also leads to a postsinusoidal block following the deposition of alcoholic hyaline in the centrilobular zone, with perivenous fibrosis and subsequent occlusion of the small veins. 

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