Fig. 11.

Nitrite-dependent NO formation by HepG2 and HMEC. (A) The in situ NO formation was followed by spectrofluorimetry, in the presence of the cell-permeant fluorescence probe 4-amino-5-methylamino-2′,7′-difluorofluorescein diacetate (DAF-FM DA); after internalization, the DAF-FM DA acetate groups are hydrolyzed, to yield DAF-FM, which will then react with the NO oxidation products (intracellular conversion of DAF-FM DA to DAF-FM). (B) The intracellular NO formation by HepG2 and HMEC is dependent on the nitrite concentration (D) and also on the dioxygen availability. (C) The contribution of XOR, AO and NOS to the measured NO was accessed using the inhibitors, allopurinol, raloxifene and L-NAME, respectively. Adapted with permission from Ref. [137]. Copyright 2015 American Chemical Society.