Repeat dearterializations seem to be a means to prevent collateral formation, which is partly responsible for the failure of hepatic artery ligation (HAL) or permanent dearterialization when used to treat liver tumors. In this study restoration of tumor blood flow was evaluated after various procedures: HAL (n = 12), permanent dearterialization (n = 18), repeated dearterializations for 2 hr/day (n = 12), and sham dearterialization (n = 12). Tumor blood flow was measured 10 days after sham dearterialization, permanent dearterialization, and repeated dearterializations for 2 hr in order to further illustrate the effect of prolonged dearterialization on tumor rearterialization. Hepatic and tumor arterial blood flow was measured using the reference organ method (NEN, 141Ce microspheres with diameter 15 microns). Our results showed that during a transient dearterialization blood flow decreased to 1% (0.01 +/- 0.01 ml/min/g) of the flow in the controls (0.82 +/- 0.10 ml/min/g) (P < 0.01). After HAL tumor blood flow recovered to initial levels after 48 hr (0.73 +/- 0.17 ml/min/g). Even in rats subjected to a permanent dearterialization blood flow was reestablished at Day 6 (0.59 +/- 0.21 ml/min/g). In contrast, after repeat daily 2-hr dearteralizations blood flow remained significantly very low during the 6th transient dearterialization (0.11 +/- 0.03 ml/min/g) compared with both sham-operation and HAL as well as permanent dearterialization (P < 0.01). During the 10th daily dearterialization tumor blood flow was still significantly low compared with both controls (P < 0.001) and permanent dearterialization (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)