Inhibition of adrenal cell aldosterone synthesis by endogenous nitric oxide release

Adrenal zona glomerulosa (ZG) cells do not contain nitric oxide (NO) syntha se (NOS). We conferred endothelial NOS activity onto adrenal ZG cells throu gh transduction with a recombinant adenovirus encoding the endothelial NOS gene (AdeNOS) to determine the effect of endogenous NO on aldosterone synth esis. A 135-kDa protein band immunoreactive to anti-endothelial NOS antibod y was observed in Western blots of AdeNOS-transduced ZG cells but not in co ntrol cells or cells transduced with adenovirus encoding the beta-galactosi dase gene (Ad beta Gal). Nitrate/nitrite production in AdeNOS-transduced ZG cells increased from 0.15+/-0.01 to 0.27+/-0.01 mu mol/L after stimulation with 1 nmol/L angiotensin Il. The treatment of AdeNOS-transduced cells wit h 30 mu mol/L L-nitro-arginine decreased angiotensin II-stimulated nitrite production from 0.27+/-0.01 to 0.17+/-0.01 mu mol/L. Basal and angiotensin II-stimulated nitrite production was not increased in Ad beta Gal-transduce d or control cells. AdeNOS-transduced cells demonstrated diaminofluorescein -2 diacetate fluorescence, which was blocked by pretreatment with L-nitro-a rginine. Angiotensin II-stimulated aldosterone synthesis decreased from 512 3+/-177 pg/mL. in Ad beta GaI-transduced ZG cells to 72+/-27 pg/mL in AdeNO S-transduced cells. Treatment with the NOS inhibitor thiocitrulline (30 mu mol/L) increased angiotensin II-stimulated aldosterone synthesis to 2158+/- 45 pg/mL after AdeNOS transduction. These data demonstrate that adenovirus- mediated gene transfer of eNOS in ZG cells results in the expression of act ive endothelial NOS enzyme and that this endogenous NO production by ZG cel ls decreases aldosterone synthesis.