Abstract: In order to research the effects of ammonia and lactic acid on suspension culture BHK-21 cell growth and intracellular enzyme activity,we cultured the BHK-21 suspension cells with the media of different concentrations of ammonia or lactic acid added,and sampled every 12 hours, determined the consumption of nutrient and vitality of succinate dehydrogenase. The results showed that when the concentration added of ammonia and lactate was below 2.5 or 10 mmol/L respectively,the ammonion and lactate had weak inhibiting effect on the growth and metabolism of BHK-21 cell. Along with the addition of ammonia and lactate,the BHK-21 cells growed more slowly, the nutrient cost reduced, the activity of succinate dehydrogenase decreased gradually. The ammonion and lactate in a concentration above 5 and 20 mmol/L had serious inhibiting effect on the growth and metabolism of BHK-21 cells,the activity of succinate dehydrogenase was always lower than the control group obviously. So the ammonion and lactate in certain concentration inhibits BHK-21 cell growth, affects the intracellular succinate dehydrogenase activity.

Key words: ammonia; lactic acid; suspension culture; glucose; succinate dehydrogenase