Department of Biotechnology, Royal Institute of Technology, SE- 100 44, Stockholm, Sweden.
Cytotechnology. 1999 Jan;29(1):45-53. doi: 10.1023/A:1008084622991.
Potassium ions decrease the transport rate of ammonium ions into myeloma and hybridoma cells, one effect of the involved transport processes being an increased energy demand (Martinelle and Häggström, 1993; Martinelle et al., 1998b). Therefore, the effects of K+ and NH4+ on the energy metabolism of the murine myeloma cell line, Sp2/0-Ag14, were investigated. Addition of NH4Cl (10 mM) increased the metabolism via the alanine transaminase (alaTA) pathway, without increasing the consumption of glutamine. As judged by the alanine production, the energy formation from glutamine increased by 155%. The presence of elevated concentrations of KCl (10 mM) was positive, resulting in a decreased uptake of glutamine (45%), and an even larger suppression of ammonium ion formation (70%), while the same throughput via the alaTA pathway (and energy production from glutamine) was retained as in the control culture. However, the simultaneous presence of 10 mM K+ and 10 mM NH4+ was more inhibitory than NH4Cl alone; an effect that could not be ascribed to increased osmolarity. Although the culture with both K+ and NH4+ consumed 60% more glutamine than the culture with NH4+ alone, the energy generation from glutamine could not be increased further, due to the suppression of the glutamate dehydrogenase pathway. Furthermore, the data highlighted the importance of evaluating the metabolism via different energy yielding pathways, rather than solely considering the glutamine consumption for estimating energy formation from glutamine.
钾离子降低了铵离子进入骨髓瘤和杂交瘤细胞的转运速率，这一转运过程的一个影响是增加了能量需求（Martinelle 和 Häggström，1993；Martinelle 等人，1998b）。因此，研究了 K+和 NH4+对鼠骨髓瘤细胞系 Sp2/0-Ag14 能量代谢的影响。添加 NH4Cl（10 mM）通过丙氨酸转氨酶（alaTA）途径增加了代谢，而不增加谷氨酰胺的消耗。从丙氨酸的产生判断，来自谷氨酰胺的能量形成增加了 155%。存在高浓度的 KCl（10 mM）是积极的，导致谷氨酰胺摄取减少（45%），铵离子形成的抑制更大（70%），而 alaTA 途径的相同通量（以及来自谷氨酰胺的能量产生）在对照培养中保留。然而，同时存在 10 mM K+和 10 mM NH4+的抑制作用比单独的 NH4Cl 更强；这种作用不能归因于渗透压的增加。尽管同时存在 K+和 NH4+的培养比单独存在 NH4+的培养消耗了 60%更多的谷氨酰胺，但由于谷氨酸脱氢酶途径的抑制，来自谷氨酰胺的能量生成不能进一步增加。此外，这些数据强调了评估不同产能途径代谢的重要性，而不仅仅是考虑谷氨酰胺消耗来估计来自谷氨酰胺的能量生成。
