Effect of atrial natriuretic factor on skin microcirculation versus skeletal muscle blood flow

The response of the skin microcirculation and of forearm skeletal muscle blood flow to infusion of alpha-human (99-126) atrial natriuretic factor (ANF) into the brachial artery was investigated in 15 young (18-25 years) healthy volunteers in a double-blind, randomized, placebo-controlled study. The forearm blood flow (FBF) was measured with venous occlusion plethysmography, and the skin flux was measured by using laser Doppler fluxmetry (LDF). Dose-response curves were made using increasing dosages of ANF: 1, 10, and 100 ng/min/dl forearm volume. The FBF showed a significant, dose-dependent increase during ANF infusion, averaging 107 +22% during the highest ANF dosage, as compared with -5 +/- 9% during placebo (p < 0.001). For the LDF, these numbers were 34 +/- 21 and 16 +/- 10%, respectively (NS). In two subgroups of subjects, the effect of ANF on microvascular reactivity was assessed by registering the vasoconstrictor response to cold exposure (n = 7) and the vasodilator response to arterial occlusion (n = 7). ANF did not change the microvascular response to these stimuli. ANF induces a dose-dependent increase in skeletal muscle BF without a relevant response in the skin microcirculation. ANF does not play an important role in the regulation of skin perfusion.