Gallstone formation in dogs after selective occlusion of the portal vein branches.

The effects of selective portal blood interruption on gallstone formation were investigated experimentally in dogs. The gallstone incidence in group I (left portal vein occlusion, N = 10) was 60 per cent at 1 month after the ligation, 64 per cent at 2 months (N = 9) and 88 per cent at 3 months (N = 8), whereas the incidence in group II (right portal vein occlusion, N = 5) was 0 per cent at 1 and 2 months (N = 5) after the ligation and 20 per cent at 3 months (N = 5). All canine gallstones, which were similar to human black stones on morphological and infrared spectroscopic examination, formed only in the gallbladders of both groups. Bile analysis showed that cholesterol, phospholipids and total bile acid concentrations in the gallbladder bile were significantly decreased in group I after the ligation. Microscopy of the gallbladders in group I showed prominent PAS-positive material in the gallbladders. Gallstone formation after portal vein occlusion is thought to depend on the extent of the area of portal blood interruption.