It has previously been demonstrated that Ukrain administration (0.5 mg in m
ice of 20 g, five times) to A/Sn mice results in retardation of HA-1 tumor
growth in the liver and a prolongation of lifespan compared with untreated
controls. In the present study Ukrain was tested as a macrophage stimulator
in intact mice and animals with HA-1 hepatoma. There were no changes to th
e carbon particles phagocytosis rate in the case of a single administration
of Ukrain to intact mice. Significant secretion of procathepsin B into asc
itic fluid was shown in tumor mice as well as marker enzyme of macrophages
beta-hexosaminidase activity suggesting an influx of macrophages into ascit
es. Single Ukrain administration increased this index, and repeated drug in
jections were followed by a tendency to normalization of secretion. The cyt
olytic effect of Ukrain against tumor cells (as a result of macrophage stim
ulation) is the most probable mechanism of its antitumor action, but this s
uggestion needs further experimental evidence with special attention paid t
o the balance of proteinases and endogenous proteinase inhibitors.