RENAL NITRIC OXIDE BIOAVAILABILITY. EFFECT OF CHRONIC TREATMENT WITH VITAMIN D

JOSE BONAPARTE; ALBERSTEIN RAMON ARIEL; CLAUDIO JOO TURONI; MARIA PERAL DE BRUNO

SAN MIGUEL DE TUCUMAN

Congreso; XXXIII ANNUAL SCIENTIFIC MEETING; 2016

FUNDACION MIGUEL LILLO

Vitamin D (VitD) has a protective effect at the vascular level, increasing levels of nitric oxide (NO) produced by NO synthases (NOS, isoforms: inducible (iNOS) and constitutive (endothelial: eNOS, and neuronal: nNOS)). A renovascular protective role is attributed to constitutive NOS. At the renal level, they are differentially distributed in cortex and medulla (iNOS predominates in medulla). Objective: To evaluate the role of VitD on renal NOS, differentiating its effect on the cortex and medulla. Methods: Wistar Kyoto male rats were divided into two groups: without (CR) and with VitD (DR: D3=750UI/kg/day for 4 weeks). Blood pressure (BP) was measured by the direct method. In kidneys, bioavailability of NO (nitrites) was evaluated by the Griess reaction differentiating cortex and medulla. NO source was evaluated by preincubation with inhibitors: Krebs without calcium plus EGTA (0Ca++: eNOS and nNOS), dexamethasone (iNOS), L-NAME (all of them); and stimulators: angiotensin 1-7 (Ang1-7: eNOS and nNOS). Results: No significant differences were observed in the BP. DR increased levels of nitrites in cortex and medulla. 0Ca++ completely inhibited nitrites in CR and DR cortex, and DR medulla. The release of nitrites in CR medulla was inhibited by dexamethasone. L-NAME completely blocked the nitrites of CR and DR. No further increases were observed in the levels of nitrites in RD incubated with Ang1-7. Conclusions: In non-hypertensive animals, VitD showed a protective role, increasing values of NO in renal cortex and medulla, mainly from the constitutive NOS. The lack of greater effect of Ang1-7 is another finding that reinforces the protective effect of VitD. A74