Renalase regulates renal dopamine and phosphate metabolism.

Renalase regulates renal dopamine and phosphate metabolism. Am J Physiol Renal Physiol. 2013 Jul 17; Authors: Sizova D, Velazquez H, Sampaio-Maia B, Quelhas-Santos J, Pestana M, Desir GV Abstract Renalase is a kidney secreted catecholamines-degrading enzyme whose expression and activity are down-regulated by increased dietary phosphate. A renalase knockout (KO) mouse model was used to explore the mechanisms mediating renalase's effect on phosphate excretion. Compared to wild type (WT) mice maintained on a regular diet, KO mice show decreased serum PO4- (KO=5.3±0.2 vs WT=6.0±0.1, n= 6, p<0.04), and increased urinary PO4- excretion (urine PO4-/creatinine: KO=7.7±0.3 vs WT=6.1±0.3, n=6, p<0.02). However, both WT and KO mice respond similarly to PO4- restriction by increasing renal COMT-1 activity and markedly decreasing PO4- excretion, which excludes an intrinsic renal defect in the KO. Renal sodium-phosphate co-transporter, Npt2a, and sodium proton exchanger, NHE3 expression, and MAO-A and B activity did not differ between WT and KO. Only catechol-O-methyl transferase (COMT) expression and activity were significantly increased in KO mice. In spite of that, urinary dopamine increased by 2 fold, while urinary L-DOPA excretion decreased by 2 fold, indicating an up-regulation of renal DA synthesis. These data indicate that renalase deficiency is associated with increased renal DA synthesis, stimulated PO4- excretion, and moderately severe ...
Source: Am J Physiol Renal P... - Category: Urology & Nephrology Authors: Tags: Am J Physiol Renal Physiol Source Type: research