The Determination of Total Circulating Serum Proteins and Erythrocyte Volumes in Normal and Protein Depleted Rats.

Abstract

A method using the dye T-1824 has been used to measure the total blood, plasma and circulating erythrocyte vols. in rats, normal and hypoprotein-ernic. No operative procedures are required as the dye is injected into a tail vein, and the blood samples, totalling approx. 0.8 ml., are obtained 5 mins. later from a small cut in a 2d tail vein. The 1st sample is collected in a 0.1 ml. pipette, and is diluted at once with a dilute albumin soln. The use of this soln. prevents errors due to variations in light absorption which arise if samples with widely differing protein concns. are diluted with salt soln. A 2d blood sample of 0.2 ml., collected in a vial containing dry oxalates, provides the 0.02 ml. sample needed to determine the Hb concn., using the Dick-Stevens photoelectric colorimeter. The oxalated sample also provides blood for obtaining the hematocrit values, from measurements of cell and plasma columns in sealed capillary tubes, after centrifugalization. The 3d blood sample, taken in a dry tube, without anti-coagulant, provides serum, for determining the serum protein concn. by the falling drop method. The concn. of the dye in the diluted whole-blood sample is detd. from readings in the Klett-Summerson colorimeter, using a 620 m[mu] filter, and with proper dye and blank controls. When these methods were used to study vol. changes in the normal and the hypoproteinemic rat good consistency was obtained. Total vols. of blood, erythrocytes and plasma were greatly reduced in the hypoproteinemic group[long dash]with values of 50-60% of those found in the controls. When expressed as unit vols., ml./100 cm.2, the avg. values for the normal and hypoproteinemic groups were: unit blood vols., 4.8 and 3.9 ml., unit erythrocyte vols. 2.2 and 1.7 ml., unit plasma vols. 2.6 and 2.2 ml./100 cm.2.