Blood, 1958, Vol. 13, No. 3, pp. 226-238.
© 1958 American Society of Hematology, Inc.
Erythrocyte Osmotic Fragility of Rats Receiving the
Thermostable Plasma Erythropoietic Factor
JAMES W. LINMAN 1 and
MARTHA J. LONG 1
1 Department of Medicine, Northwestern University Medical School and the
Veterans Administration Research Hospital, Chicago, Illinois.
1. The thermostable erythropoietic factor in "anemic" rabbit plasma stimulates cellular division of marrow erythrocytic precursors in the normal rat producing erythrocytosis due to microcytes without evidence of augmented hemoglobin synthesis.
2. Study of erythrocyte osmotic behavior in these animals with a quantitative photocolorimetric method failed to demonstrate significant variation from
the controls.
3. Osmotic fragility determinations by a direct cell enumeration technic revealed decreased resistance of the microcytes to lysis in hypotonic sodium
chloride solutions.
4. It is concluded from these data that the erythrocytes in the normal rat
injected with the heat stable plasma erythropoietic factor comprise two distinct
cell types. They are microcytes with shortened survival times and normal
erythrocytes.
5. The decreased viability of these microcytes is the apparent explanation
for the rapid re-establishment of normal erythrocytic equilibrium after the
"anemic" plasma extract injections are stopped.
Submitted on July 1, 1957
Accepted on September 15, 1957
