A more pronounced effect of iodixanol on afferent than on efferent arterioles may contribute to the reduction of glomerular filtration rate in contrast medium-induced acute kidney injury. Decreased nitric oxide bioavailability and increased concentration of superoxide explain the increased tone and reactivity in afferent arterioles perfused with iodixanol.

A sex-specific, nitric oxide-mediated effect via angiotensin II type 2 receptors underlies the sex differences in the response of interlobar arteries to angiotensin II. Our findings may help understanding sex differences in renal hemodynamics and blood pressure control.

We tested the influence of estrogen on coronary resistance regulation by modulating nitric oxide (NO) and hydrogen peroxide (H2O2) levels in female rats. For this, estrogen levels were manipulated and the hearts were immediately excised and perfused at a constant flow using a Langendorff's apparatus. Higher estrogen levels were associated with a lower coronary resistance, increased nitric oxide bioavailability, and higher levels of H2O2. When oxide nitric synthase blockade by L-NAME was performed, no significant changes were found in coronary resistance of ovariectomized rats. Additionally, we found an inverse association between NO levels and catalase activity. Taken together, our data suggest that, in the absence of estrogen influence and, therefore, reduced NO bioavailability, coronary resistance regulation seems to be more dependent on the H2O2 that is maintained at low levels by increased catalase activity.

Hypertension plays a negative role on the development of diabetic nephropathy, increasing the mortality of patients. Moderate exercise training decreases oxidative stress and is a therapy for cardiovascular and metabolic diseases. The aim was to determine the effect of exercise on renal oxidative stress and mortality of spontaneous hypertensive diabetic rats (SHR + streptozotocin 50mg/Kg; 3 months old) randomized into: sedentary (S, n=8) and trained (T, n=8) groups. After moderate exercise training (treadmill ‐ 1h/day, 5days/wk, 10wk), kidney was excised for measurement of oxidative damage (lipoperoxidation–LPO) and antioxidant enzymes activity (superoxide dismutase–SOD, catalase–CAT, and glutathione peroxidase–GPX activity) (Student's t‐test; Kaplan‐Meier method). T group presented lower renal LPO (T=1199± 184; S=2549± 111 counts/second/mg protein), higher renal antioxidant enzymes activity (SOD:T=10.6± 0.7; S=8.3± 0.4 U/mg protein; CAT:T=23722; S=164± 17 pmol/mg protein; GPX:T=7.8± 0.3; S=6.4± 0.5 nmol/min/mg protein; p<0.05) and lower mortality (p=0.03). Our results show that moderate exercise training reduces oxidative stress and suggests that this adaptation may decrease mortality of hypertensive diabetic animals. Financial Support: FAPESP, CNPq.

The objective was to determine the effect of treatment with an ACE inhibitor, enalapril (EN), on cardiac oxidative stress. Male Kyoto and SHR (15 wks) were treated for 10 weeks with EN or control (gavage, 10 mg/kg, n = 7/group). After treatment, blood pressure (BP) and heart rate were recorded from an arterial catheter (Windaq, 2KHz). Rats were euthanized with collection of heart with measurement of cardiac index (ventricle weight/body weight; mg/g), chemiluminescence (CL) and carbonyl assay. Akt and MAPK (Erk and p38) expression were assessed by Western blot. Results are presented as mean ± SD (table). In SHR, enalapril reduced BP, cardiac hypertrophy and p38 expression, probably due to a decreased cardiac oxidative stress caused by renin‐angiotensin system.Supported by: CNPq and FAPERGS.