[Plasma volume in polycystic kidney disease].

Hypertension is a common and serious complication of autosomal dominant polycystic kidney disease (ADPKD), occurring early in the course of the disease. Disorders of tubular transport of sodium and increased plasma and blood volume (PV and BV), as a consequence, are thought to be involved in the pathogenesis of hypertension in ADPKD. In order to evaluate PV and BV in early stage of ADPKD, PV and BV were measured with radioactive serum albumin dilution technique. Three groups of subjects with normal glomerular filtration rate were studied: ADPKD hypertensive (ADPKD H, n = 10, age: 36.2 +/- 8.7 y), ADPKD normotensive (ADPKD N, n = 15, age: 33.4 +/- 7.4 y), and healthy volunteers (C, m = 8, age: 32.6 +/- 6.8 y). PV and BV expressed per kilogram of body weight did not differ among the 3 groups. When PV and BV were expressed per meter square of body surface area, diminished BV in the group ADPKD H in comparison to ADPKD N and group c (p < 0.05) was found, other parameters did not differ between the 3 groups. In conclusion--our results do not support the hypothesis of a significantly increased PV and BV of patients with ADPKD prior to the onset of hypertension.