Nowak G, Schnellmann R G
Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock 72205-7199, USA.
Am J Physiol. 1996 Dec;271(6 Pt 1):C2072-80. doi: 10.1152/ajpcell.1996.271.6.C2072.
The addition of L-ascorbic acid 2-phosphate (AscP) to primary cultures of rabbit renal proximal tubular cells (RPTC) grown under improved culture conditions resulted in an extended growth phase and increased cellular density (1.3-fold increase in monolayer DNA and protein contents). AscP reduced glycolysis, increased net lactate consumption by 38%, and stimulated net glucose production by 47%. Basal O2 consumption increased by 39% in RPTC grown in the presence of AscP and was equivalent to that in freshly isolated proximal tubules. AscP increased ouabain-sensitive O2 consumption (81%) and Na(+)-K(+)-ATPase activity (2.5-fold), which suggested increased active Na+ transport. Addition of AscP increased Na(+)-dependent glucose uptake by 43% and brush-border enzyme marker activities by 46%. It is concluded that supplementation of media with AscP further improves RPTC culture conditions by promotion of cellular growth and stimulation of in vivo-like respiration, lactate utilization, and net glucose synthesis. These changes are accompanied by an increase in brush-border enzyme activities and stimulation of active Na+ transport and Na(+)-dependent glucose transport, which demonstrate an improved expression of brush-border membrane functions in RPTC.
在改良培养条件下生长的兔肾近端小管细胞（RPTC）原代培养物中添加L-抗坏血酸2-磷酸酯（AscP），可使生长阶段延长，细胞密度增加（单层DNA和蛋白质含量增加1.3倍）。AscP减少了糖酵解，使净乳酸消耗量增加38%，并刺激净葡萄糖生成增加47%。在存在AscP的情况下生长的RPTC中，基础氧气消耗量增加了39%，与新鲜分离的近端小管中的基础氧气消耗量相当。AscP增加了哇巴因敏感的氧气消耗量（81%）和钠钾ATP酶活性（2.5倍），这表明主动钠转运增加。添加AscP使钠依赖性葡萄糖摄取增加43%，刷状缘酶标志物活性增加46%。结论是，在培养基中添加AscP可通过促进细胞生长以及刺激类似体内的呼吸、乳酸利用和净葡萄糖合成，进一步改善RPTC培养条件。这些变化伴随着刷状缘酶活性增加以及主动钠转运和钠依赖性葡萄糖转运受到刺激，这表明RPTC中刷状缘膜功能的表达得到改善。
