A histochemical study about the zonal distribution of the galactose-binding protein in rat liver.

1. Dog intestinal alkaline phosphatase (IAP), an asialoglycoprotein, appeared to be a good marker for the histochemical detection of the galactose specific binding protein in cryostat sections of rat liver. 2. Binding of IAP to the receptor is optimal at neutral and slightly alkaline pH values. The binding could be inhibited by galactose and galactose containing sugars, whereas glucose and mannose did not show any effect. In contrast to fetuin itself desialylated fetuin completely inhibited IAP binding. Pretreatment of sections with phospholipase C or with trypsin inhibited IAP binding; collagenase did not show any influence. 3. The presence of the galactose-binding protein showed a distinct zonal distribution. In the area around the central vein (zone 3) the highest IAP binding capacity was found.