EFFECT OF ERYTHROPOIETIN ON TRITIATED THYMIDINE INCORPORATION BY THE RAT SPLEEN
The action of erythropoiesis-stimulating factor (ESF, erythropoietin) obtalned from the plasma of anemic rabbits was demonstrated by measuring the uptake of H/sup 3/-labeled thymidine by rat spleen. The splenic incorporation of thymidine in ESF-stimulated animals was significantly elevated over control values at all time intervals studied (15 to 180 min). Maximum labeling occurred at 60 min, with the 180-min values being essentially equal to those obtained at 60 min. The values reflect tissue proliferative activity since under the stimulus of ESF, thymidine uptake is increased by a factor of 4. The 60-min values most directly reflect DNA incorporation of label and indicate the DNA synthetic capacity of tissues. In order to study the effect of ESF on cells of the reticuloendothelial system (RES) in spleen, the animals were made hypoxic (maintained in a 7.7% O atmosphere) and irradiated (800 r, whole-body 220-kv x rays). Acute hynoxia was shown to protect against x radiation. Although the absolute number of splenic RES cells was not increased by irradiation, their relative counts in spleen increased 5-fold 96 hr after irradiation. Spleen weight decreased 36 to 46% and was not affected by injection of ESF. Body weight and hematocrit remained normal but circulating reticulocyte count fell after irradiation and was not restored by ESF. ESF injection also failed to stimulate the incorporation of thymidineH/sup 3/ in RES cells, indicating its selective effect on hemopoietic cells. (H.H.D.)
- Research Organization:
- Northwestern Univ., Chicago
- NSA Number:
- NSA-17-019853
- OSTI ID:
- 4733435
- Journal Information:
- Journal of Laboratory and Clinical Medicine (U.S.), Journal Name: Journal of Laboratory and Clinical Medicine (U.S.) Vol. Vol: 61; ISSN JLCMA
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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