The aim of this study was to evaluate the renal response to atrial extracts (AE) and synthetic atrial natriuretic factor (ANF) in control rats and in rats with experimental nephrotic syndrome (NS). NS was obtained by a single intravenous injection of adriamycin (7.5 mg/kg). Bolus injection of AE from normal or NS rats resulted in marked increase in diuresis and natriuresis in bioassay control rats (AE from normal rats, urine flow rate, 14.87 ± 2.94 to 186.18 ± 55.86 μl/min; Na excretion, 0.68 ± 0.26 to 21.80 ± 5.45 μeq/min; AE from NS, urine flow rate, 13.49 ± 4.30 to 167.14 ± 51.44 μl/min; Na excretion, 0.98 ± 0.57 to 20.71 ± 9.76 μeq/min). In contrast, blunted diuretic (from 11.26 ± 3.05 to 65.20 ± 27.30 μl/min) and natriuretic (from 0.58 ± 0.15 to 4.52 ± 1.59 μeq/min) effect was observed when AE were injected in rats with NS. Injection of the vehicle in which AE were dissolved or ventricular extracts did not increase urinary flow rate or Na excretion in both control and NS animals. Bolus injection of synthetic ANF (Arg-101-Tyr-126) induced marked diuretic and natriuretic response in control but not in NS rats. Similar results were obtained when AE were infused by constant infusion in control or in NS bioassay rats. AE given by constant infusion induced comparable increase in glomerular filtration rate (GFR) over basal values both in control and NS animals (controls, 39%; NS rats, 40%). These results show that 1) the diuretic and natriuretic response to AE or synthetic ANF, although present, is markedly attenuated in NS compared with control animals; and 2) the abnormal diuretic and natriuretic response occurs despite a comparable percentage increase in GFR. It is suggested that ANF-induced natriuresis and diuresis may be at least partially independent of the increase in GFR.
|Title of host publication||American Journal of Physiology - Renal Fluid and Electrolyte Physiology|
|Publication status||Published - 1987|
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