RRC ID 39754
Author Choi YS, Lee DY, Kim IY, Kang S, Ahn K, Kim HJ, Jeong YH, Chun GT, Park JK, Kim IH.
Title Ammonia removal using hepatoma cells in mammalian cell cultures.
Journal Biotechnol Prog
Abstract It was examined whether hepatocyte cell lines can be used for ammonia removal in mammalian cell cultures. It was found that there exists a critical ammonium concentration level for each hepatocyte cell to remove ammonia. Among the cells tested in this work, primary hepatocytes showed the strongest ammonia removal capability if ammonium concentration is higher than the critical level. However, primary hepatocytes lost the liver function gradually and finally died after 2-3 weeks. Because of this limitation, primary hepatocytes were not appropriate to be used for ammonia removal in long-term cultures. Hep G2 cells, which are immortal, also showed a strong ammonia removal activity. The ammonia removal activity of Hep G2 cells depended on the concentration of ammonium in the medium, as in the case of primary hepatocytes. However, urea could not be detected in the course of ammonia removal by Hep G2 cells. Instead of urea, Hep G2 cells secreted glutamine into the culture medium. The capacity for ammonia removal was higher in the absence than in the presence of glutamine. Thus we checked the activity of glutamine synthetase in the Hep G2 cells. The level of glutamine synthetase activity increased with the addition of ammonium chloride. This result accounts for the ammonium concentration dependency of Hep G2 cells in ammonia removal and glutamine synthesis. Furthermore Hep G2 cells could grow well in the absence of glutamine, which was necessarily required in mammalian cell cultures. These results prove that glutamine formation serves as the primary mechanism of detoxifying ammonia in hepatocyte cell lines as expected. In addition, it was demonstrated that ammonium level could be reduced 38% and that erythropoietin production increased 2-fold in the mixed culture of Hep G2 and recombinant CHO cells.
Volume 16(5)
Pages 760-8
Published 2000-1-1
DOI 10.1021/bp000099d
PII bp000099d
PMID 11027167
MeSH Ammonia / metabolism* Animals CHO Cells Cells, Cultured Coculture Techniques Cricetinae Glutamate-Ammonia Ligase / metabolism Liver / cytology Liver / enzymology Liver / metabolism* Liver Neoplasms, Experimental / enzymology Liver Neoplasms, Experimental / metabolism* Liver Neoplasms, Experimental / pathology Rats Rats, Sprague-Dawley Urea / metabolism
IF 2.334
Times Cited 17
WOS Category FOOD SCIENCE & TECHNOLOGY BIOTECHNOLOGY & APPLIED MICROBIOLOGY
Resource
Human and Animal Cells F-36E(RCB0776)