430
Chapter 12
The physiology of the HGFs is very complex because
(1) there are so many types, (2) any given HGF is often pro-
duced by a variety of cell types throughout the body, and (3)
HGFs often exert other actions in addition to stimulating
blood cell production. There are, moreover, many interactions
of the HGFs on particular bone marrow cells and processes.
For example, although erythropoietin is the major stimula-
tor of erythropoiesis, at least 10 other HGFs cooperate in the
process. Finally, in several cases the HGFs not only stimulate
differentiation and proliferation of progenitor cells, but they
inhibit the usual programmed death (apoptosis) of these cells.
The administration of specifi c HGFs is proving to be of
considerable clinical importance. Examples are the use of eryth-
ropoietin in persons having a defi ciency of this hormone due to
kidney disease, and the use of granulocyte colony-stimulating
factor (G-CSF) to stimulate granulocyte production in indi-
viduals whose bone marrow has been damaged by anticancer
drugs.
Pluripotent
hematopoietic
stem cell
Lymphoid
stem cell
Myeloid
stem cell
Lymphocyte
Erythrocyte
Neutrophil
Monocyte
Eosinophil
Basophil
Platelets
Megakaryocyte
Figure 12–71
Production of blood cells by the bone marrow. For simplicity, no attempt has been made to differentiate the appearance of the various precursors.
Adapted form Golde and Gasson.
Table 12–12
Reference Table of Major Hematopoietic Growth Factors (HGFs)
Name
Stimulates Progenitor Cells Leading To:
Erythropoietin
Erythrocytes
Colony-stimulating factors (CSFs) (example: granulocyte CSF)
Granulocytes and monocytes
Interleukins (example: interleukin 3)
Various leukocytes
Thrombopoietin
Platelets (from megakaryocytes)
Stem cell factor
Many types of blood cells
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