Effects of modulation of GGT activity on GSNO-mediated ^•NO production in aortic tissue.

<p>Panel A: ^•NO production from rat aortic rings exposed to GSNO (1 mM) or GSNO (1 mM) in the presence of SBC (20 mM), glycylglycine (20 mM) or L-NAME (300 µM). Data are means ± SEM of 4–7 experiments, * p<0.05 <i>versus</i> GSNO. Panels B, C, D: representative fluorescence micrographs (×20) of 10-µm sections of rat aortic rings loaded for 2 h with 4,5-diaminofluorescein diacetate (DAF-2 DA, 10 µM) showing ^•NO production following 15-min incubation with GSNO (1 mM, panel C) or GSNO in the presence of SBC (20 mM, panel D) or glycylglycine (20 mM, panel B). Scale bar, 50 µm. All pictures were captured under constant exposure time, gain and offset.</p

Histochemical localization of GGT activity in rat aortic tissue.

<p>Typical micrographs (×16) corresponding to histochemical visualization of γ-glutamyltransferase (GGT) activity in endothelium-intact rat aortic rings prepared in the presence of γ-glutamyl-4-methoxy-2-naphthylamide (GMNA, panel A) or in the presence of GMNA and SBC (20 mM, panel B) and in endothelium-denuded aortic rings prepared in the presence of GMNA (panel C). Scale bar, 100 µm.</p

Influence of GGT activity on the vasorelaxant effect of GSNO.

<p>Concentration-dependent vasorelaxation response curves of GSNO (•), GSNO with glycylglycine (20 mM) (Δ), GSNO with acivicin (50 µM) (◊), GSNO with SBC (20 mM) (□), and GSNO with ODQ (5 µM) (○) in endothelium-intact (panel A) and endothelium-denuded (panel B) aortic rings. Panel C: pD2 values (panel C). Data are means ± SEM of 4–12 aortic rings per group. p values (2 ways ANOVA test): p_interaction <0.0001; p_endothelium <0.0001; p_modulator_{of GGT} <0.0001. * p<0.05 <i>versus</i> GSNO endothelium-intact; $ p<0.05 <i>versus</i> GSNO endothelium-denuded (post-hoc Bonferroni test). ** p<0.05 versus GSNO in endothelium-intact aortic rings (one way ANOVA test).</p

Specific GGT activity and GSH consumption rate in rat aorta homogenates.

<p>Specific activity of γ-glutamyltransferase (GGT) and consumption rate of GSH measured in rat aorta homogenates incubated in Tris buffer pH 7.4 with and without SBC (20 mM) or glycylglycine (20 mM). Data are means ± S.E.M. of 3 experiments. (*p<0.05 versus Control; ND^#: not detected – below limit of detection).</p

Effects of modulation of GGT activity on GSNO consumption in rat aorta homogenates.

<p>Consumption rates of GSNO measured in rat aorta homogenates incubated in Tris buffer pH 7.4 with and without SBC (20 mM) or glycylglycine (20 mM). Data are means ± SEM of 3 experiments, * p<0.05 <i>versus</i> substrate alone.</p