Hemodynamic responses, renal function, and plasma levels of immunoreactive atrial natriuretic factor (irANF) were examined following volume expansion (VE) in normal (N) conscious dogs and in conscious dogs with cardiac denervation (CD). Base-line urine flow was consistently greater (P less than 0.05) in dogs with CD (0.54 +/- 0.06 ml/min) than in N (0.29 +/- 0.03 ml/min) dogs but sodium excretion did not differ between N (2.80 +/- 0.58 mu eq.min-1.kg body wt-1) and CD (3.53 +/- 0.75 mu eq.min-1.kg-1) groups. With VE (18 ml/kg of 3% dextran in saline), mean arterial pressure (MAP) increased (P less than 0.01) by 16 +/- 3 from 103 +/- 4 mmHg in N dogs but did not change from pre-VE base line (103 +/- 2 mmHg) in dogs with CD. At 10 min after VE, urine flow increased more (P less than 0.01) in N dogs (1.39 +/- 0.24 ml/min) than in dogs with CD (0.26 +/- 0.09 ml/min). At that time, increases in sodium excretion were also greater (P less than 0.01) in N (9.13 +/- 1.96 mu eq.min-1.kg-1) dogs than in dogs with CD (1.06 +/- 0.68 mu eq.min-1.kg-1). With VE, increases in irANF plasma levels were not different in N dogs (40 +/- 12 from 34 +/- 5 pg/ml) and in dogs with CD (27 +/- 3 from 45 +/- 7 pg/ml). In dogs with CD, when MAP was increased by aortic constriction to mimic responses observed in N dogs, renal responses were similar to those of N dogs.(ABSTRACT TRUNCATED AT 250 WORDS)