Experimental Studies on the Influences of Spleen on the Hematopoietic Function of Bone Marrow Part 1. Influences of Splenectomy, Homoioplastic Transplantation of Spleen, and of Spleen Extract on the Erythropoietic Function of the Rabbit Bone Marrow

With the purpose to study the influences of the spleen on the erythropoietic function of bone marrow the cell suspension culture of the rabbit bone marrow was conducted, and the following results were obtained. 1. In the bone-marrow tissue culture of splenectomized rabbits conducted from time to time the rate of the increase in the number of erythrocytes is temporarily accelerated having its peak around 4 to 7 days after the operation as compared with the control, while on the contrary, the increase in hemoglobin declines slightly. About three weeks after the operation both values of erythrocytes and hemoglobin return approximately to those in the control group, normal ones without splenectomy. 2. In the bone-marrow tissue culture of the rabbits transplanted with hemoioplastic spleenand conducted from time to time, the rate of the increase in the number of erythrocytes temporarily declines having the minimum around the fifth day after the operation and the rate of the increase in hemo-globin falls slightly around the fifth day but by around the thenth day it shows a slight acceleration, as compared with those of the control, rabbits transplanted with normal kidney. However, after about 30 days both of these values return approximately to those of the control. 3. In the observations of the bone-marrow tissue culture of normal rabbits with addition of Ringer's solutions of normal rabbit spleen extract at various concentrations, the extract at a higher concentration brings about the fall in the increasing rate of erythrocytes and hemoglobin, while on the contrary it brings about a slight acceleration in the increasing rate of both at a lower concentration. 4. From these results it is assumed that the spleen of the normal rabbit with the aid of some body-fluid agent adjusts the erythropoietic function of the bone marrow either suppressingly or acceleratingly, but from the physiological aspect the suppressing action seems to be superior: namely, an abnormal formation of the erythrocyte series is suppressed, while on the other hand the hemoglobin synthesis seems to be accelerated, thus suppressing the incomplete maturation of erythrocytes.