Background: Glucose-6-phosphate dehydrogenase (G6PD) regulates production of the reduced form of NADPH through the pentose phosphate pathway. G6PD may therefore affect superoxide anion production via vascular NADPH oxidase, which is key in mediating the vascular response to angiotensin II (Ang II). We determined the hypertensive and vascular hypertrophic response to Ang II in G6PD-deficient mice.
Methods and results: Ang II (0.7 mg/kg per day) was infused via subcutaneous osmotic pumps for 6 days in male hemizygote G6PD mutant (G6PD(mut)) and wild-type (WT) C3H mice. (1) Compared with WT, G6PD(mut) mouse aorta had 10% to 20% of G6PD activity and 50% less NADPH. (2) Basal systolic blood pressure was not significantly different in G6PD(mut) mice (WT 88+/-4 mm Hg versus G6PD(mut) 95+/-4 mm Hg), but Ang II increased blood pressure to a lower level in G6PD(mut) mice (WT 139+/-4 mm Hg versus G6PD(mut) 123+/-5 mm Hg; P<0.05). (3) Ang II increased aortic medial thickness less in G6PD(mut) mice (WT 71+/-2 mum versus G6PD(mut) 62+/-1 mum; P<0.01). (4) 3-o-Nitrotyrosine staining and dihydroethidium oxidation in the aorta was increased by Ang II less in G6PD(mut) mice. (5) Smooth muscle cells isolated from G6PD(mut) mice showed less Ang II-induced phosphorylation of Akt and p42/44 ERK.
Conclusions: G6PD deficiency may reduce vascular superoxide anion production by limiting production of the substrate for NADPH oxidase, thereby inhibiting oxidant-mediated Ang II-induced signaling pathways that contribute to hypertension and smooth muscle hypertrophy.