Measurement of the cardiac output and its peripheral distribution in rats by means of radioactive microspheres

Abstract

The cardiac output (CO), the blood flow (BF) through several organs and the peripheric resistances have been simultaneously determined on uninephrectomized rats by using two kinds of microsphere with a theoretical diameter of 15 micrometer and labeled with 141Ce or 85Sr.The measured diameter of the microspheres was 13.1 +/- 0.2 micrometer (n = 500) for the 141Ce labeled microspheres and 16.2 +/- 0.3 micrometer (n = 500) for the 85Sr ones.The difference is statistically significant (p < 0.005).Both kinds of microspheres gave comparable values for the CO and the renal, splenic and heart coronary; BF, but quite dissimilar for the hepatic and pulmonary BF.the resulting CO (29.0 +/- 2.4 ml/min-1/100 g-1) is very similar to those reported in the literature and likewise with the splenic, coronary and renal BF, correlating the latter closely with the value obtained from the PAH clearance.In conclusion, the microspheres technique seems to be a simple and timesaving method to measure the CO and BF of such organs as kidneys, spleen and heart of the rat.