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Arterial hypertension is found in as many as 75% patients with autosomal dominant polycystic kidneys with normal renal function, its pathogenesis is however not quite clear so far. The authors examined 16 patients with polycystic kidneys with normal or only slightly reduced renal function (plasma creatinine lower than 140 umol/l), 8 of these patients were normotonic (N) and 8 hypertonic (H). In all examined subjects right-sided cardiac catheterization was performed with assessment of the minute cardiac volume by thermodilution. To all patients in the course of one hour 1500 ml saline per 70 kg body weight were administered and the haemodynamic examinations were repeated after termination of the infusion. In all subjects before and after expansion the plasma renin activity was assessed (PRA), as well as plasma aldosterone (PA), plasma catecholamines (PC) and the atrial natriuretic factor (ANF), the renal blood flow and glomerular filtration by means of clearance and extraction of PAH and inulin clearance. The authors did not find differences in plasma concentrations, cardiac output and splanchnic and renal ANF extraction in groups N and H, nor in PRA, PA and PC. Volume expansion led in both groups to a comparable rise of ANF and suppression of PRA and PA. Group H did not differ from group N in any of the investigated haemodynamic and renal parameters except for systemic vascular resistance. In hypertensive patients before expansion a close correlation was found between pressure in the pulmonary artery in a wedged position and diuresis (r = 0.935, p less than 0.01) and natriuresis (r = 0.895, p less than 0.01). The volume expansion was in both groups associated with a comparable rise of diuresis, the haemodynamic response of patients N and H was however quite different. While in patients of group N a decline of the systemic vascular resistance occurred as well as an increase of the minute volume without a change of the renal flow and glomerular filtration, in hypertonic patients the systemic vascular resistance and minute volume did not change but there was a significant rise of the renal flow and glomerular filtration. The relationship of diuresis and natriuresis of hypertensive patients with polycystic kidneys to volume parameters and the rise of the renal perfusion pressure during volume expansion indicates the importance of pressure natriuresis for ensuring the sodium and volume homeostasis in these patients.

The authors examined, using nephrological, genealogical and molecular genetic methods, 85 subjects from 19 families with autosomal dominant heredity of polycystic kidney disease. Using the probe 3HVR alpha-globin and restriction endonuclease Pvu II, the authors assessed 95% informative families in the given group and the reliability of the diagnosis was also 95%. The authors tested the homogeneity of the disease in the Czech population and the applicability of the mentioned probe and endonuclease for molecular genetic testing of our population.

Using nephrological, genealogical and molecular genetic methods, the authors examined 85 members of 19 families with autosomal dominant polycystic kidney disease. With the aid of probe 3'HVR, alpha-globin and restriction endonuclease Pvu II, the families were found 95% informative. The rate of diagnostic reliability was also 95%. The authors verified the homogeneity of the disease in the Czech population and the applicability of the probe and endonuclease for molecular gene diagnostics in the population.