Differential localization of sulfotransferase isoenzymes in rat liver

Liver sections prepared from male and female rats were immunohistochemically stained with the antisera against phenol sulfotransferase G (P-STG), an isoenzyme of phenol ST as well as androsterone-sulfating ST (AD-ST), an isoform of hydroxysteroid ST. Localization of these isoenzymes in liver is sex-dependent and is markedly different between the two. P-STG is preferentially localized in the hepatocytes proximal to the central vein in females, whereas it is present in all the hepatocytes throughout the liver in males. On the other hand, AD-ST is evident in the hepatocytes proximal to the portal triad in males, while in females it is synthesized and localized in all the hepatocytes. The polarized sex-related localization of these ST isoenzymes appears to correlate with differential hormonal regulation of the enzymes.