[Resistance to the action of atrial natriuretic peptide and urodilatin in Heymann nephritis in vitro].
We examined renal sodium handling in rats with Hymann nephritis (HEN), an immunologically mediated model of nephrotic syndrome. Rats were studied 9-14 days following i.p. injection of anti-Fx1A antiserum. We previously demonstrated that HEN had a blunted volume expansion natriuresis (2% body weight isotonic saline infused over 5 min), excreting sodium at only half the rate of normal controls (CTL) despite similar increase in plasma atrial natriuretic peptide (ANP) concentration. Urinary excretion of cGMP accumulation by isolate glomeruli and inner medullary collecting duct (IMCD) cells in response to increasing concentration of ANP, and RNP (also called urodilatin). Results (fmol/mg prot/10 min) are means +/- SEM: [table: see text]. Basal accumulation of cGMP was not different among the groups, HEN rats hd reduced cGMP accumulation in response to ANP, and RNP. In binding studies using 125I-ANP, no difference in either density or affinity was found between CTL and HEN rats. Thus, there is a renal resistance to ANP in rats with HEN, which can be extended to other agents acting through the cGMP pathway. This resistance is not due to impaired binding of ANP, but to impaired accumulation of cGMP in responsive tissues, reflecting perhaps increased cGMP catabolism by phosphodiesterase. Such an observation may account for the altered sodium handling in nephrotic rats.
Valentin
J P
JP
Department of Medicine, San Francisco General Hospital, CA, USA.
Ying
W Z
WZ
Sechi
L A
LA
Humphreys
M H
MH
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D006152:Cyclic GMP / Q000032:analysis; D004232:Diuretics / Q000494:pharmacology*; D004351:Drug Resistance; D007106:Immune Sera / Q000009:adverse effects; D008297:Male; D009318:Natriuresis; D009404:Nephrotic Syndrome / Q000139:chemically induced / Q000378:metabolism*; D010446:Peptide Fragments / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017461:Receptors, Atrial Natriuretic Factor / Q000032:analysis
D004232:Diuretics; D007106:Immune Sera; D010446:Peptide Fragments; C056452:Ularitide; D009320:Atrial Natriuretic Factor; D017461:Receptors, Atrial Natriuretic Factor; D006152:Cyclic GMP
Résistance aux actions du peptide natriurétique atrial et de l'urodilatine dans la néphrite de Heymann in vitro.