Abstract
The extensive use of white rat for blood studies in the field of nutrition and physiology makes it highly desirable to have a method for following changes in the blood volume of this animal. It is obvious that such a method as to sacrifice the animal in measuring the blood volume is of little value in blood studies where it is desired to follow changes in the blood volume over a period of time.
Thus, the author modified and made it easier to measure the plasma volume of the rat by the plasma-dye method which has been so successfully used in the case of the larger animals and human subjects. An accurately measured volume of Evans Blue (T-1824) is injected into blood stream through a tail vein which is exposed by cutting a small portion of the skin surgically. After exactly 4 minutes, the blood is drawn by the heart puncture for analysing the concentration of the dye in the plasma.
Values obtained by this method are compared with the previous available data on volume studies in the rat and are found favorable agree with them.
The results varied with the body size of the rats, but the unit plasma volume which is expressed in ml per surface area is almost constant among the entire group of this study.
Thus, a formula to predict the blood volume of the normal rat is constructed on the basis of the data obtained and, is as follows:
Plasma volume (ml) =3.61S-1.78
S: surface area calculated by Lee's formula
