Blood flow and blood volume in a transplanted rat fibrosarcoma: comparison with various normal tissues

Blood flow measurements following i.v. infusion of iodo-antipyrine labelled with 14C(14C-IAP) and blood volume measurements following i.v. injection of 125I human serum albumin and 51Cr-labelled red blood cells were made in a transplanted rat fibrosarcoma for comparison with various normal tissues. The tumour-blood partition co-efficient for 14C-IAP was found to be 0.79 +/- 0.07 which is similar to most of the normal tissues studied. The solubility of 14C-IAP in plasma was found to be higher than that in whole blood. Blood flow to tumours less than 1000 mm3 was found to be 17.9 +/- 4.0 ml blood 100 g tissue-1.min-1. These values were considered to be primarily measurements of nutritive flow. Blood in the tumours was found to occupy around 1% of the tissue space which was similar to that found for normal muscle and skin. There was no direct correlation between % blood volume and blood flow for the different tissues studied. The haematocrit of blood contained in tumour tissue was calculated to be significantly lower than that of blood contained in the normal tissues. It was suspected that permeability of tumour blood vessel walls to 125I-HSA could have accounted for this difference.