The relation of periportal fibrosis to portal hypertension.

To clarify the relation of periportal fibrosis to portal hypertension, the present study was undertaken in rats given lithocholate. Portal vascular resistance measured by an isolated liver perfusion method increased with the length of lithocholate administration. In vivo portal vein pressure elevation was closely correlated to the increase in portal vascular resistance. The blood pressure difference between the portal vein and the terminal portal venule increased compared to control rats. The blood pressure differences between the terminal portal venule and the terminal hepatic venule, and between the terminal hepatic venule and the inferior vena cava, were almost the same as those in control rats. Lithocholate administration induced narrowing and meandering of the portal vein branches due to periportal fibrosis with proliferation of bile ductules. There was no perceptible change in the sinusoids and the hepatic vein branches. These data suggest that periportal fibrosis causes deformation of the peripheral branches of the portal vein and leads to presinusoidal portal hypertension.