Effect of atrial natriuretic factor on renal function in rats with papillary necrosis.

The current study was designed to evaluate whether the renal papilla participates in the natriuretic and diuretic response to atrial natriuretic factor (ANF). Papillary necrosis was induced in female rats by intravenous infusion of 2-bromoethylamine hydrobromide (BEA) 48 h prior to clearance experiments; untreated (UNT) animals served as controls. Rats were anesthetized with pentobarbital sodium, tracheotomized, and catheters placed in a femoral artery and vein and in the bladder. At the time of surgery, the bladder urine was collected and its osmolality used as an indication of papillary destruction. Mean urine osmolalities (+/- SE) of BEA rats were significantly lower than those of UNT rats (443 +/- 10 vs. 1,229 +/- 57 mosmol/kg, respectively), indicating that BEA caused papillary necrosis. Synthetic ANF (rat 8-33) was given as a bolus intravenously (1.25, 2.5, 5.0 micrograms/kg). The ANF-induced increases in sodium excretion were not significantly different between UNT and BEA rats at any ANF dose. These results demonstrate that a functional papilla is not required for the action of ANF in the rat.