The aim of this study was to assess the hemodynamic effects of acute and chronic administration of
vapreotide, a
somatostatin analog, in rats with intrahepatic
portal hypertension induced by
dimethylnitrosamine (DMNA) administration. Acute effects were evaluated at baseline and 30 min after placebo (N = 13) or
vapreotide (8 /microg/kg/hr, N = 13) infusions in DMNA rats. Chronic hemodynamic effects were evaluated using subcutaneous implants for five weeks in anesthetized DMNA rats (placebo: N = 13,
vapreotide: N = 13) and in
sham rats (placebo: N = 10,
vapreotide: N = 10). Hemodynamic measurements included
splenorenal shunt blood flow (SRS BF) by the transit time ultrasound (TTU) method and cardiac output by the combined dilution-TTU method. Acute administration of
vapreotide significantly decreased SRS BF (-17.3 +/- 19 vs - 1.1 +/- 14%, P < 0.05) and portal pressure (-8 +/- 9 vs 0 +/- 8%, p < 0.05) compared to placebo without systemic effects. Chronic administration of
vapreotide significantly reduced the increase in SRS BF (2.4 +/- 1.5 vs 1.2 +/- 1.0 ml/min, P < 0.05) and cardiac index (50 +/- 15 vs 33 +/- 10 ml/min/100 g, P < 0.0001) while portal pressure and blood flow, and mean arterial pressure were not significantly changed compared to placebo. In conclusion, the acute administration of
vapreotide decreased collateral circulation blood flow while chronic administration attenuated its development.
Vapreotide seems to have a vasoconstrictive effect on collateral circulation.