Effects of NO on CXCR4 expression. Effects of DETA NONOate in the presence or absence of L-NAME on (A) nitrate/nitrite production, (B) CXCR4 mRNA expression, and (C) CXCR4 protein expression. K1 and B-CPAP cells were treated with 1 mM DETA NONOate in the presence or absence of L-NAME for various time periods and prepared for (A) measurement of nitrate/nitrite production, (B) real-time RT-PCR analysis, and (C) western blot analysis, as described in Materials and Methods. Determinations were performed in triplicate and expressed as mean of three experiments ± SE. (A) Control indicates cells with no treatment. (B-C) Data was expressed as ratio of mRNA or protein levels relative to control (untreated) cells. * indicates significant difference (p < 0.05) from control and/or L-NAME-treated cells.