L-NAME-treatment alters ectonucleotidase activities in kidney membranes of rats.
OBJECTIVE
To investigate the effect of N(omega)-Nitro-L-arginine methyl ester (l-NAME) treatment, known to induce a sustained elevation of blood pressure, on ectonucleotidase activities in kidney membranes of rats.


METHODS
L-NAME (30 mg/kg/day) was administered to Wistar rats for 14 days in the drinking water. Enzyme activities were determined colorimetrically and their gene expression patterns were analyzed by semi-quantitative RT-PCR. The metabolism of ATP and the accumulation of adenosine were evaluated by HPLC in kidney membranes from control and hypertensive rats. PKC phosphorylation state was investigated by Western blot.


RESULTS
We observed an increase in systolic blood pressure from 115+/-12 mmHg (control group) to 152+/-18 mmHg (l-NAME-treated group). Furthermore, the hydrolysis of ATP, ADP, AMP, and p-Nph-5'TMP was also increased (17%, 35%, 27%, 20%, respectively) as was the gene expression of NTPDase2, NTPDase3 and NPP3 in kidneys of hypertensive animals. Phospho-PKC was increased in hypertensive rats.


CONCLUSIONS
The general increase in ATP hydrolysis and in ecto-5'-nucleotidase activity suggests a rise in renal adenosine levels and in renal autoregulatory responses in order to protect the kidney against the threat presented by hypertension.
Fürstenau
Cristina Ribas
CR
Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
Ramos
Denise Barbosa
DB
Vuaden
Fernanda Cenci
FC
Casali
Emerson André
EA
Monteiro
Priscilla de Souza
Pde S
Trentin
Danielle da Silva
Dda S
Gossenheimer
Agnes Nogueira
AN
Bogo
Maurício Reis
MR
Bonan
Carla Denise
CD
Barreto-Chaves
Maria Luiza Morais
ML
Sarkis
João José Freitas
JJ
Wofchuk
Susana Tchernin
ST
D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology*; D002851:Chromatography, High Pressure Liquid; D003404:Creatinine / Q000097:blood; D004195:Disease Models, Animal; D015870:Gene Expression / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D006973:Hypertension / Q000097:blood / Q000201:enzymology* / Q000503:physiopathology; D007668:Kidney / Q000187:drug effects / Q000201:enzymology* / Q000503:physiopathology; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction
D003404:Creatinine; D000251:Adenosine Triphosphatases; C027201:ectoATPase; D019331:NG-Nitroarginine Methyl Ester