Atriopeptins: circulating volume regulatory hormones with potential therapeutic role in chronic renal failure.

Sprague-Dawley rats given bolus intravenous injections of vasoconstrictors, including 1-deamino-Arg8-vasopressin (dAVP), demonstrated remarkable increases in plasma immunoreactivity (APir) to atriopeptin (AP). These elevations were accompanied by increases in systemic blood pressure, right atrial pressure and urinary volume excretion. Fractionated plasma APir peaks obtained by stimulation with dAVP were identified as primarily AP 28, with a smaller amount of AP 24, suggesting that AP 28 is the predominant circulating atrial peptide. Rats with reduced renal mass have increased single-nephron glomerular filtration rates (GFR). Despite these increases, AP 24 stimulated a marked increase in total GFR and promoted a profound natriuresis and diuresis. Atriopeptin 24 may therefore have potential as a therapeutic tool in the management of volume overload in chronic renal failure.