Atrial natriuretic factor and generalized edema in rats
Velhote, V.W.; Fujihara, C.; Marcondes, M.
Brazilian Journal of Medical and Biological Research 18(4): 481-485
1985
ISSN/ISBN: 0100-879X PMID: 2942206 Document Number: 245544
The natriuretic action of the atrial natriuretic factor (ANF) was studied in massively proteinuric, anti-natriuretic and edematous nephrotic rats with moderate impairment of renal function. Animals were distributed among four groups: NA----NR, NV----NR, NeA----NR and NA----NeR, where normal atrial (NA) or normal ventricular (NV) or "nephrotic" atrial (NeA) extracts were injected (----) into normal rats (NR) or nephrotic rats (NeR). Control (C) clearance measurements were made before iv injection of the extracts and at four 15-min intervals thereafter (E). Mean arterial pressure and glomerular filtration rate did not change consistently in all four groups from the C to the E period. However, during the first 15-min period after extract injection, statistically significant fractional natriuretic peaks of 332, 361 and 662% of preinjection control values were demonstrable for the NA----NR, NeA----NR and NA----NeR groups, respectively, but not for NV----NR. Following the natriuretic peak, natriuresis returned to control values for NA----NR, but remained above control levels for the NeA----NR and NA----NeR groups. We conclude that, since both the atrial extract from nephrotic rats injected into normal rats and the atrial extract from normal rats injected into nephrotic rats elicited marked natriuresis, the anti-natriuretic edematous condition observed in nephrotic animals cannot be attributed either to the absence of ANF in their atria or to the unresponsiveness of their kidneys to ANF.