FIGURE 5.

Effects of extracellular sodium replacement on Me-AIB uptake, SNAT2, and SNAT5 gene expression. (A) Basal Me-AIB uptake was assayed in HeLa cells using uptake buffer containing a physiological Na concentration or one in which the cation was replaced with an equimolar concentration of TMA. (B–D) HeLa cells were cultured in DMEM media and subsequently incubated for 8 h in EBSS or buffer in which Na had been replaced with an equimolar concentration of TMA that contained or lacked a 1× physiological AA mix. Cells were subsequently washed and harvested for analysis of SNAT2, SNAT5, and GAPDH gene expression by quantitative PCR analysis of RNA (B,D) or analysis of SNAT2 protein (C) in total membranes isolated from cells. Data in bar graphs are presented as mean ± SEM (n = 3) with asterisks indicating significant changes (P < 0.05) between the indicated bars.