Key Points
- To distinguish the physiologic cardiovascular, renal, and endocrine effects of atrial natriuretic factor from actions that occur only at pharmacologic concentrations.
- Infused alpha-human atrial natriuretic factor (alpha-h-ANF) stepwise at 0.0025, 0.005, 0.01, and 0.3 micrograms/kg/min into pentobarbital-anesthetized dogs (n = 10).
- Monitored changes in circulating ANF concentrations, urinary fluid and electrolyte excretion, proximal tubular sodium handling, and central hemodynamics.
- At the lowest infusion rate, circulating ANF increased by 31 ± 3 pg/ml, triggering significant increases in absolute sodium excretion, fractional excretion of sodium, and fractional excretion of lithium alongside decreased urine osmolality, without altering glomerular filtration rate.
- A larger circulating ANF increase (96 ± 12 pg/ml) was needed to significantly decrease right atrial pressure, cardiac output, and plasma renin activity, while increasing systemic vascular resistance and potassium excretion.
- Reductions in systemic arterial pressure and renal vascular resistance were observed solely at the pharmacologic infusion rate of 0.3 micrograms/kg/min.
Structured PICO
PPopulationPentobarbital anesthetized dogs (n = 10)
IInterventionStepwise infusion of alpha-human atrial natriuretic factor (alpha-h-ANF) at 0.0025, 0.005, 0.01, and 0.3 micrograms/kg/min
OOutcomeChanges in absolute sodium excretion, fractional excretion of sodium, fractional excretion of lithium, and urine osmolalitysurrogate
Atrial natriuretic factor acts as a natriuretic and diuretic at physiologic concentrations, while higher concentrations are required to decrease cardiac output, filling pressure, and renin activity, and even higher doses to decrease arterial pressure.