Plasma volume, cell volume, total blood volume and Fcells factor in the normal and splenectomized Sherman rat

Abstract

A method is described for the catheterization of the carotid of the rat which permits blood volume determinations to be made on unanesthetized animals. The cell volume (P³²) and plasma volume (T-1824) were measured simultaneously on the day after catheterization. The average F_cells factor was 0.739 (S.D., 0.053) in 11 normal rats and 0.726 (S.D., 0.041) in 10 splenectomized rats. In 50 unanesthetized normal rats the plasma volume averaged 3.90 ml/100 gm body weight. The blood and cell volumes calculated by using the F_cells factor of 0.74 and the separately determined plasma trapping' factor of 0.95 averaged 5.93 ml/ 100 gm and 2.14 ml/100 gm, respectively. These values agree closely with those determined from the simultaneous measurement of cell and plasma volumes and also with the values obtained on 27 normal rats under ether.