Key result
A bolus injection of 8 micrograms/kg of synthetic human ANF in sheep fetuses decreased fetal arterial pressure by 2 mmHg, increased heart rate by 15 beats/min, and increased urine flow rate to 250% of control.
Why the study?
Does atrial natriuretic factor affect vascular pressures and fluid dynamics in sheep fetuses?
Does atrial natriuretic factor affect vascular pressures and fluid dynamics in sheep fetuses?
In sheep fetuses, atrial natriuretic factor induces transient cardiovascular and fluid dynamic changes, including decreased arterial pressure and blood volume, and increased urine flow.
No immediate implications for human fetuses; leaves open ANF's role in ovine fetal hemodynamics.
Presently little is known about the effects of atrial natriuretic factor (ANF) in the fetus. In this study we explored the effects of ANF on vascular pressures and fluid dynamics in the chronically catheterized sheep fetuses averaging 133 days gestation (term = 145-150 days). Under resting conditions plasma ANF concentration was positively correlated with fetal heart rate (P less than 0.001) and was not correlated with arterial pressure, venous pressure, or plasma osmolality. The weight-normalized fetal urine flow rate correlated positively with ANF concentration (P less than 0.01). After a bolus injection of 8 micrograms/kg of synthetic human ANF into the inferior vena cava, fetal arterial pressure decreased by 2 mmHg and remained at this level for 60 min, venous pressure was unchanged, and heart rate increased transiently by 15 beats/min. Urine flow rate increased to 250% of control 5 min after the injection and returned to control at 20 min even though ANF was four times control levels. Fetal blood volume decreased significantly by 5% within 10 min and remained low for 60 min. This decrease in blood volume was greater than the increase in urine flow. A kinetic analysis revealed that ANF disappearance from the plasma could not be adequately characterized with a single rate constant due to exchange between plasma and interstitial fluid.(ABSTRACT TRUNCATED AT 250 WORDS)
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Brace et al. (1987) studied this question. Synthetic human atrial natriuretic factor (ANF) vs. Baseline/control conditions was evaluated on Vascular pressures and fluid dynamics (arterial pressure, venous pressure, heart rate, urine flow rate, blood volume). A bolus injection of 8 micrograms/kg of synthetic human ANF in sheep fetuses decreased fetal arterial pressure by 2 mmHg, increased heart rate by 15 beats/min, and increased urine flow rate to 250% of control.
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