Effect of glucose on systemic hemodynamics and blood flow rate in normal and tumor tissues in rats

The effect of hyperglycemia on systemic hemodynamics and blood flow rate of Walker 256 carcinoma and several normal tissues of unanesthetized, unrestrained female Sprague-Dawley rats was measured, using the radioactive microsphere technique prior to and at 30 and 60 min after glucose administration (6 g/kg body weight i.v.). Whereas the mean arterial pressure and heart rate remained unchanged following glucose injection, cardiac output (CO), cardiac index, and stroke volume decreased by approximately 25% (P less than 0.05), and the total peripheral resistance increased by more than 25% (P less than 0.05). Redistribution of blood flow, expressed as a percentage of CO, among normal tissues was traced to the brain, kidneys, spleen, and liver and away from the skin, pancreas, and stomach. Changes in percentage of CO to the jejunum, colon, peritumor muscle, hindlimb, and forelimb muscles were not significant. Reduction in blood flow in large tumors (greater than 0.6 g) was proportional to the reduction in CO, and in small tumors (less than 0.6 g) was more than the reduction in CO. These results suggest that the reduction in blood flow due to hyperglycemia in large tumors is primarily due to reduction in CO and in small tumors due to both systemic and local effect; and changes in the blood flow to normal tissues should not be disregarded when using hyperglycemia in combination with hyperthermia and/or chemotherapy for cancer treatment.