Production of Erythropoietin (EPO), a hematopoietic factor, with a recombinant CHO (Chinese hamster ovary) cell was studied. When sodium butyrate was added to the culture medium, cell proliferation was severely inhibited but specific erythropoietin production was enhanced by 7-fold compared with that of the control without addition of sodium butyrate. In order to evaluated the possiblity of deglycoslyation effect of sodium butyrate, the glycosylated pattern of EPO samples obtained was analyzed by using'Lectin-blotting sysem'. No specific deglycosylation effects could be found. As a negative control, ammonium chloride was applied to investigate the effect of the ammonia concentration in the medium. By treating 8 mM to above, the specific productivity of EPO decreased to a half level of the control and sialylation of carbohydrate chain was found to be substantially inhibited. Chloroquine was also applied to study the deglycosylation effect. The treatment of chloroquine severely decreased the production of EPO and glycosylation was strongly inhibited. At the concentration of 100 μM and 200 μM, terminal sialic acid process was prevented. And at the concentration of 300 μM, N-acetyllactosamine chain synthesis was found to be inhibited
