Bone marrow sinus cell packing: a determinant of cell release
JK Chamberlain, L Weiss and RI Weed
Ultrastructural studies of erythropoietin effects on the bone marrow of
control and hypertransfused (65 hct) mice revealed a decrease in
adventitial cell cover of the sinus apertures in erythropoietin-treated
animals. A more striking finding, however, was the marked inhibition of
erythropoietin-induced reticulocytosis by hypertransfusion itself.
Hypertransfusion of the erythropoietin-treated animals appeared to decrease
the reticulocyte response by inhibiting reticulocyte response by marrow
cords in addition to inhibiting erythroid proliferation. This inhibition of
reticulocyte response was associated with clustering of reticulocytes
around the marrow sinuses which were packed with red cells. Acute lowering
of the hematocrit of erythropoietin-treated, hypertransfused animals to
normal at the time of maximal reticulocyte response in control animals
resulted in more than a twofold increase in reticulocytosis with 2 hr. It
is suggested that (1) elevated levels of erythropoietin are associated with
a diminution of the normal marrow- peripheral blood barrier, thereby
contributing to the premature release of marrow elements and (2) the
hematocrit is an important determinant of cell release from the marrow into
the peripheral circulation.
Volume 46,
Issue 1,
pp. 91-102,
07/01/1975
Copyright © 1975 by The American Society of Hematology
