The blood supply of experimental liver metastases. VIII. Increased capillary blood flow within liver tumors with administration of epinephrine.

Capillary blood flow has been studied with a laser doppler probe in normal liver tissue and within Walker carcinosarcoma tumors implanted in the livers of rats. Epinephrine, in doses from 1 to 100 micrograms injected as a bolus into the portal system caused immediate significant rises in tumor capillary blood flow. These effects lasted approximately 1 minute and were followed by secondary decreases in flow. Aortic blood pressures rose with epinephrine administration and remained elevated for periods longer than the increase in tumor capillary flow. The effects of epinephrine on liver capillary flow were dose related; doses of 5-10 micrograms caused a decreased flow, 3 micrograms produced a biphasic response, and 1 microgram resulted in an increase in flow. It is concluded that epinephrine produces a short but significant increase in capillary blood flow within the central parts of these tumors, in areas previously considered "avascular".