Possible Mechanisms Involved in the Natriuretic Response to Atrial Natriuretic Factor (Anf) and Proanf 31–67 in the Rat

The present study was conducted to compare the mechanisms involved in the natriuretic response to atrial natriuretic factor (ANF) and proANF 31-67. The peptides were infused intravenously into anaesthetized rats at 10 pmol/min for 40 min. 2. Only ANF produced a significant decrease in arterial pressure; the maximum decrease was 11 mmHg (P < 0.05). 3. Both peptides produced significant increases in sodium excretion (P < 0.05) but only ANF increased the cyclic GMP (cGMP) excretion rate (P < 0.01) and neither peptide had a significant effect on plasma renin activity or glomerular filtration rate (GFR). ProANF 31-67 did not increase the plasma levels of ANF. 4. These results demonstrate that both ANF and proANF 31-67 have natriuretic effects via a tubular mechanism and suggest that the natriuretic effects of ANF are mediated by cGMP while the excretion, changes in GFR or a reduction in renin secretion.