Chronic administration of propylthiouracil ameliorates hyperdynamic circulation in portal hypertensive rats.

ABSTRACT

OBJECTIVE: To evaluate the effect of a hypothyroid state, induced by chronic propylthiouracil administration, on splanchnic and systemic hemodynamic parameters in rats with portal hypertension due to portal vein ligation. METHODS: Portal hypertension was induced by surgical stenosis of the portal vein. Cardiac index and portal blood flow were measured using radioactive microspheres. Measurements were performed after treatment with propylthiouracil (1 mg/ml in drinking water) for 5 days. RESULTS: Propylthiouracil-treated portal hypertensive rats had a lower portal pressure (12.4 +/- 1.9 versus 16.3 +/- 0.7 mmHg; p < 0.05) and portal blood flow (11.6 +/- 0.7 versus 13.2 +/- 1.3 ml/min/100 g; p < 0.05) than non-treated animals. Splanchnic vasoconstriction in treated animals was associated with a higher peripheral vascular resistance (2.3 +/- 0.4 versus 1.8 +/- 0.3 mmHg/ml/min/100 g; p < 0.05) than controls. CONCLUSION: These results suggest that portal pressure can be lowered by inducing a hypothyroid state by chronic administration of propylthiouracil.