Endogenous atrial natriuretic factor after endopeptidase 24.11 inhibition by Thiorphan

The neutral endopeptidase 24.11 (NEP) was shown to degrade atrial natriuretic factor (ANF) in kidney membranes. An infusion of Thiorphan (25 micrograms/min/kg x 90 min), a specific NEP inhibitor, induced an increase in plasma ANF (65 +/- 26 to 163 +/- 52 pg/ml), plasma renin activity and in norepinephrine concentrations at 50 minutes of infusion in conscious rabbits. The increase in plasma ANF was accompanied by a gradual decrease in renal blood flow, despite maintenance of a stable mean arterial pressure. In conclusion, Thiorphan infusion produced an increase in endogenous plasma ANF. However, it may also have affected other hormonal systems which may have contributed to the overall dynamic and hormonal profile documented.