Atrial natriuretic peptide alters neither capillary filtration nor vascular compliance of both skin and skeletal muscle of humans.

We studied the effects of hANP 99-126 on capillary filtration and venous compliance in both the calf (mainly skeletal muscle) and foot (mainly skin) of humans. Six healthy mean received ANP (intravenous injection of 25 micrograms followed by continuous infusion of 0.1 microgram.kg-1.min-1) for 30 min. Another six men served as time controls. Capillary filtration coefficient, venous compliance, and also volume and blood flow of both calf and foot were measured repeatedly by occlusion plethysmography before, during, and after ANP. Additionally, we determined hematocrit, central venous pressure, venous pressure in the foot, arterial pressure, and heart rate. Filtration coefficients, venous compliance, blood flow of both calf and foot as well as arterial blood pressure did not change systematically during the infusion of ANP, and yet leg volume and central venous pressure (3.1 +/- 0.8 cm H2O) decreased while both hematocrit (3.1 +/- 1.0%) and heart rate (17 +/- 11 min-1) increased. Thus, the ANP-evoked decrease in central venous pressure and increase in hematocrit are unrelated to blood pooling or increases in capillary filtration in skeletal muscle and skin of healthy humans.