BONE MARROW BLOOD VOLUME AND TOTAL RED CELL MASS OF THE GUINEA-PIG AS DETERMINED BY 59-FE-ERYTHROCYTE DILUTION AND LIQUID NITROGEN FREEZING.

Abstract

The blood content and circulating red cell volumes of bone marrow and lymphoid tissues have been determined by means of a 59Fe‐labelled erythrocyte technique coupled with liquid nitrogen freezing in male guinea‐pigs. The marrow blood volume represented 4·90–6·96 per cent of the total marrow volume and showed regional differences which have been partially correlated with marrow cellularity. It has been calculated that the entire bone marrow of the guinea‐pig normally contains 1·7 per cent of the whole body blood volume and 2·0 per cent of the whole body circulating red cell mass. At 3 hr. after the injection of labelled erythrocytes there was evidence of a selective pooling in the spleen and bone marrow of recipient animals.The whole body blood volume was calculated to be 5·91 ml./100 g. body weight and the ratio of body hæmatocrit to cardiac hæmatocrit was 0·846.A comparison of the numbers of circulating erythrocytes in marrow (isotope dilution technique) with total erythrocyte numbers determined in suspensions of disrupted marrow was in accord with the view that the non‐nucleated, non‐reticulated marrow erythrocytes are intravascular.