Role of Xanthine Oxidase in Dexamethasone‐induced Hypertension in Rats

Abstract

1. Glucocorticoid-induced hypertension (GC-HT) in the rat is associated with nitric oxide-redox imbalance. 2. We studied the role of xanthine oxidase (XO), which is implicated in the production of reactive oxygen species, in dexamethasone-induced hypertension (dex-HT). 3. Thirty male Sprague-Dawley rats were divided randomly into four treatment groups: saline, dexamethasone (dex), allopurinol plus saline, and allopurinol plus dex. 4. Systolic blood pressures (SBP) and bodyweights were recorded each alternate day. Thymus weight was used as a marker of glucocorticoid activity, and serum urate to assess XO inhibition. 5. Dex increased SBP (110 +/- 2-126 +/- 3 mmHg; P < 0.001) and decreased thymus (P < 0.001) and bodyweights (P" < 0.01). Allopurinol decreased serum urate from 76 +/- 5 to 30 +/- 3 micromol/L (P < 0.001) in saline and from 84 +/- 13 to 28 +/- 2 micromol/L in dex-treated (P < 0.01) groups. 6. Allopurinol did not prevent dex-HT. This, together with our previous findings that allopurinol failed to prevent adrenocorticotrophic hormone induced hypertension, suggests that XO activity is not a major determinant of GC-HT in the rat.

Xanthine oxidase and mitochondria contribute to vascular superoxide anion generation in DOCA-salt hypertensive rats

“…Our study is the first in which DOCA-salt rats received a XO inhibitor. Data have been previously reported on the effect of XO activity on BP (20,29). We were unable to find evidence of enhanced XO activity by measuring uric acid plasma or enzymatic activity in the liver from DOCAsalt rats.…”

Antihypertensive effect of allicin in dexamethasone-induced hypertensive rats

“…In the experimental rats, hypertension was induced by subcutaneous injection of dexamethasone (10 μg/kg/d) in the evening 13, 14…”

Lipid Peroxidation and Antioxidants in Arterial Hypertension

“…Antihypertensive effect Lack of antihypertensive effect Apocynin Prevented/attenuated mineralocorticoid-induced hypertension [86,240] Prevented/reversed glucocorticoid-induced hypertension [241] Prevented/reversed adrenocorticotropic hormone-induced hypertension [242] Prevented the development of Ang II-induced hypertension in mice [186] Prevented the development of renovascular hypertension [243] Prevented the development of hypertension induced by RAS activation [50] Reduced blood pressure in borderline and spontaneous hypertension [244] Attenuated salt-sensitive hypertension [245] Normalized blood pressure in a model of hypertension induced by disruption of dopamine D2 receptor [246] Failed to prevent the hypertension induced by chronic infusion of endothelin-1 [200] Failed to prevent hypertension in transgenic mice overexpressing renin or angiotensinogen [247,248] Failed to prevent Ang II-induced hypertension in rats [249,250] Gp91ds-tat Attenuated the blood pressure rise induced by Ang II in mice [209] Failed to attenuate salt-sensitive hypertension [251] Allopurinol Attenuated salt-sensitive hypertension [252] Prevented glucocorticoid-induced hypertension [253] Failed to prevent or attenuate mineralocorticoid-induced hypertension [254] Failed to prevent glucocorticoidinduced hypertension [255] Failed to prevent or attenuate adrenocorticotropic-induced hypertension [242] Failed to prevent the development of hypertension induced by the blockade of nitric oxide synthesis [256] Failed to prevent the progression of hypertension in young SHR [257] Oxypurinol Reduced blood pressure in SHR [258] Tempol Attenuated hypertension in SHR [201] Prevented the progression of hypertension in saltloaded SHRSP [259] Attenuated mineralocorticoid-induced hypertension [260] Failed to prevent Ang II-induced hypertension [264] Failed to attenuate hypertension induced by inhi...…”