Presence of the atrial natriuretic factor (ANF) in human ascitic fluid

The actions of human atrial natriuretic factor on hepatic arterial and portal vascular beds of the anaesthetized dog

1. The vascular actions of atrial natriuretic factor (ANF) have been assessed with other vasoactive agents on the hepatic arterial and portal vascular beds of the anaesthetized dog. 2. Intra-arterial bolus injections of ANF (0.1-50 nmol) caused graded increases in hepatic arterial blood flow representing a vasodilatation of relatively short duration. Vasoconstriction was never observed. 3. The maximum increase in hepatic arterial blood was the same for ANF and isoprenaline (Iso) i.e. approximately 60-70% increase over control flow. 4. On a molar basis, ANF was less potent than Iso although over the higher dose range (10(-9)-10(-7) mol) its vasodilator activity exceeded that of the endogenous vasodilator adrenaline. 5. Intraportal bolus injections (1.0-50 nmol) of ANF did not alter portal inflow resistance since no changes in portal inflow pressure occurred when the portal circuit was perfused at constant inflow volume. 6. This differential action of ANF on the hepatic arterial and portal vascular beds may provide a change in total liver blood flow in favour of the arterial component. 7. ANF, by altering hepatic haemodynamics to favour formation of trans-sinusoidal fluid exchange, may provide a temporary expansion of the extravascular fluid reservoir to buffer any increased venous pressure. However, chronically elevated plasma levels of ANF would encourage the formation of ascitic fluid.

Presence of immunoreactive atrial natriuretic peptides in pericardial fluid of human subjects with congenital heart diseases

The epicardial release of immunoreactive atrial natriuretic peptides (ir-ANPs) in inside-out perfused rabbit atria has been reported. In order to determine the presence of ir-ANPs in pericardial fluid and to evaluate their biochemical characteristics, we measured the concentration of ir-ANPs in pericardial fluid obtained from the patients with congenital heart diseases during open heart surgery. Serial dilution curves made with the extrats of pericardial fluid using Sep-Pak C18 cartridges were parallel with standard curve. The concentration of ir-ANPs in pericardial fluid was significantly lower than the corresponding plasma concentration. On gel permeation and reverse-phase high performance liquid chromatography, the ir-ANPs in pericardial fluid, plasma and atrial appendage showed both high and low molecular weights. The major peak of ir-ANPs in plasma was observed at the corresponding fraction to the alpha-human ANP and considerable amount of high molecular weight form of ir-ANPs was observed in pericardial fluid. However, the major peak of ir-ANPs in atrial appendage was observed at the corresponding fraction to the rat pro-ANP. The data suggest that ir-ANPs exist both high and low molecular weight forms in pericardial fluid.