Cardiac Output (CO) Distribution in Mice Bearing Lewis Lung Carcinoma (3LL) or JW sarcoma (JWS), two Spontaneously Metastasizing Tumours

The study of blood supply to tumours and metastases is of interest for a better u ‘erst ding of tumour biology and for pharmacological approaches. A radioactive microspheres method was developed to assess CO distribution in C57B1/6J mice bearing syngeneic 3LL or Balb/c mice with JWS. At the initial stages of cancer growth, the CO relative fractions per g of tissue (%CO/g) to 3LL and JWS were similar to those in surrounding tissues. The both tumours a positive, significant correlation was found between tumour weight and tumours CO fraction but % CO/g was lower in 3LL, 2 and 3 weeks after transplantation whereas it. did not change in JWS. Indeed, much larger necrotic areas developed in 3LL than in JWS. The % CO/g to the lungs increased in both models when metastases were not yet visible; subsequently, the appearance of lung nodules was accompanied by decrease of % CO/g in J and a further increase in 3LL. This corresponded to the much higher ratio of metastatic to intact lung tissue in JWS than in 3LL. In fact, isolated lung metastases had a signicantly lower blood supply than the surrounding tissue. This might be due to a different vascularization pattern and/or smaller amounts of vasodilator substances being produced by metastatic nodules; the latter is suggested by lower generation of prostacyclin acti vity in isolated lung metastases than in intact pulmonary tissue.