The influences 1-stepholidine(1-SPD)on the hepatic blood flow (HBF) in anaesthetized rats were studied by investigating the elimination rate of

113m

In in blood. The value of HBF of normal rats was 0.89±0.17(SD)ml/min per g liver calculated from the K value (0.447±0.070 min

-1

)

which was consistent with the value (0.90±0.17 ml/min per g liver) determined by other method.

1-SPD decreased the HBF like Iso

with doses of 10

20 and 40mg/kg i. v.

but the latter could not be antagonized by propranolol. 1-SPD(20mg/kg) was able to antagonize the increasing HBF effects of NE like phentolamine. It is suggested that the hypotension effect of 1-SPD may be resulted from its α-adrenoceptor blocking effect.