Summary
A boiled extract acidified to pH 5.5 from the blood plasma of partially hepatectomized
rats was treated with neuraminidase and injected i.p. into untreated rats. The DNA-synthesis
of the liver cells showed a four-fold increase in comparison with controls. Extracts
from the plasma of partially hepatectomized rats without neuraminidase treatment showed
no increase in DNA-synthesis. Injections of boiled acid extracts from plasma of normal
rats, however, showed no comparable differences before and after neuraminidase treatment.
The activity of neuraminidase treated boiled, plasma extract is lost after treatment
both with trypsin-chymotrypsin and with β-galactosidase. Gel chromatography of the
factor gave a molecular weight of about 38,000 D. The specific activity of the active
extract after chromatography was raised by a factor of 300. According to affinity
chromatography the factor was shown to be a glycoprotein containing N-Ac-glucosamine.
The factor is inert with respect to the proliferation of spleen and kidney, i.e. it
is organ specific.
According to these results a regulatory system of hepatopoiesis is proposed.
Key-Words
Rat
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Partial Hepatectomy
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Liver Cell Proliferation Factor
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Characterization
