[Control of the quality of radioimmunological methods of determining plasma levels of atrial natriuretic peptide (ANP) and the evaluation of their usefulness in clinical studies].

The radioimmunologic assays appeared to be the most convenient methods for determination of atrial natriuretic peptide (ANP) concentration in blood plasma. The purpose of this work was to compare the control quality parameters of two radioimmunologic methods for the ANP determination in human plasma: the methods described by Pruszczyński et al. and the method with the use of Amersham ready-made set (kit). The comparison of the two methods was performed by analyzing 10 series of ANP determinations carried out by Pruszczyński method, and 15 series by means of the kit. Both methods appeared to fulfil the criteria of satisfactory quality for RIA determinations. The second purpose of this study was to define the utility of the RIA method for the determination of ANP in clinical practice, taking into the consideration some factors influencing or modifying plasma ANP levels. Three groups of persons of were studied: 15 healthy subjects, 16 patients with acromegaly and 47 patients with the impairment of renal function. The ANP level in plasma was determined in these 3 groups of persons. It has been demonstrated that the change of body position from upright to supine caused the increase of the ANP concentration in plasma. It has also been found that the decrease in the intravascular fluid volume induced by furosemide administration resulted in the reduction of ANP concentration in plasma. The enlarged intravascular fluid volume, accompanying acromegaly and probably present in persons with the impairment of kidneys, was associated with the increased ANP concentrations in plasma.