Hematocrit and Erythrocyte Volume Determinations in the Goat as Related to Spleen Behavior

Abstract

Studies on the blood and circulation in the goat show that they possess some features which, while common to other species, are present in the goat to an exaggerated degree. The fraction of plasma retained among the erythrocytes in hematocrit determinations made in the usual manner was much larger than in other species. The percentage increase in the hematocrit immediately following intravenous injections of adrenaline was larger in some animals than reported values for dog and man. The concentration of erythrocytes in the venous blood of goats was frequently variable even in the same animal under different experimental conditions. The time-concentration curves obtained during erythrocyte volume determinations by means of Cr51-labeled cells were often anomalous and suggested that mixing of the labeled cells with total body cells was slow under some circumstances. This was confirmed by determinations associated with adrenaline injections. Also, experiments in which counts were determined in the splenic region of an intact animal following injections of Cr51-labeled cells showed slow accumulation. The spleen was found to be quantitatively responsible for most of the adrenaline response since the effect was very small in splenectomized animals. It is probable that the spleen is also responsible for much of the slow mixing of labeled cells and the variability of the hematocrit.