Effect of angiotensin II on blood flow in the transplanted sheep squamous cell carcinoma

The effects of systemic infusion of angiotensin II on the distribution of blood flow in the sheep squamous cell carcinoma after transplantation to the liver were measured using tracer microspheres. The ratio of arterially introduced radioactive microspheres embolizing in tumour tissue compared to normal hepatic parenchyma was measured before and after infusion of angiotensin II. Doses of angiotensin II inducing increases in mean arterial blood pressure of 26 mmHg produced significant increases in the embolization ratio from 2.8 to 4.1:1. In addition, the ratio of microspheres gaining access to the necrotic centres of the tumours compared to the normal liver tissue significantly increased from 1.6 to 2.3:1. In terms of the technique of internal radiation therapy for hepatic metastases, the concurrent infusion of angiotensin II with injection of radioactive microspheres would result in a substantially enhanced radiation dose to liver tumours. At the same time the dose to normal tissue can be minimized.