Effect of portal hypertension caused by chronic high venous pressure on small-intestinal sugar absorption.

The effect of portal hypertension and chronic high venous pressure on the absorption of the small intestine was examined by constricting the suprahepatic and subdiaphragmatic inferior vena cava in rats. A group of rats with the constricted suprahepatic and subdiaphragmatic inferior vena cava comprised group 1 (n = 9) and another group of rats with only laparotomy comprised group 2 (n = 9). Two months after the operation, sugar absorption and other parameters were measured. The blood pressures of the infrahepatic inferior vena cava and the portal vein 8 wk after the operation in group 1 were significantly higher than those in group 2. The results of D-xylose absorption tests showed that the amount of excreted D-xylose in urine in group 1 was significantly lower than that of group 2, but the D-xylose everted sac test showed no significant differences between the two groups. The glucose everted sac test showed that the amount of glucose absorption in group 1 was significantly lower than that in group 2. These findings suggest that chronic high venous pressure caused by constriction of suprahepatic inferior vena cava may lead to sugar malabsorption. We conclude that portal hypertension with high venous pressure below the diaphragm can lead to sugar malabsorption in the intestine.