Table 2 U-osmolality (U-Osm), urine excretion of aquaporin2 (u-AQP2), urine output (UO), and free water clearance (C_H2O) during a water deprivation test in patients with adult dominant polycystic kidney disease (ADPKD), patients with non-ADPKD kidney disease (Non-ADPKD), and healthy control subjects (Controls). Urine was collected in four periods. Period 1 (twelve hours): from 0730 PM the day before arrival to the laboratory to 0730 AM on the examination day. Period 2 (one hour): 0730 to 0830 AM. Period 3 (two hours): 0830–1030 AM. Period 4 (two hours): 1030–1230 AM

 ADPKD

498 ± 149

518 ± 143*

491 ± 133*

569 ± 105*

 Non-ADPKD

496 ± 220

603 ± 143*

532 ± 192*

579 ± 114*

 Controls

620 ± 233

765 ± 150

694 ± 198

757 ± 167

Comparison within groups

Comparison between groups

 ADPKD

1.6 ± 0.7

1.3 ± 0.5*

1.8 ± 1.1*

1.3 ± .5*

 Non-ADPKD

1.5 ± 0.6

1.0 ± 0.3*

1.6 ± 0.7*

1.2 ± 0.4*

 Controls

1.1 ± 0.6

0.7 ± 0.3

1.0 ± 0.5

0.9 ± 0.3

Comparison within groups

Comparison between groups

 ADPKD

−0.8 ± 0.5

−0.9 ± 0.5

−0.9 ± 0.8

−1.1 ± 0.4

 Non-ADPKD

− 0.8 ± 0.7

−1.0 ± 0.5

−0.9 ± 0.5

−1.1 ± 0.4

 Controls

− 0.9 ± 0.5

−1.1 ± 0.5

−1.1 ± 0.4

−1.3 ± 0.3

Comparison within groups

Comparison between groups

 ADPKD

0.8 ± 0.3

0.9 ± 0.4*

0.7 ± 0.3*

0.8 ± 0.2*

 Non-ADPKD

0.8 ± 0.6

1.0 ± 0.5*

0.7 ± 0.4

0.8 ± 0.2*

 Controls

1.1 ± 0.5

1.5 ± 0.6

1.1 ± 0.7

1.1 ± 0.4

Comparison within groups

Comparison between groups

 ADPKD

0.6 [0.2;0.8]

0.7 [0.4;1.5]*

0.5 [0.3;0.9]*

0.6 [0.3;0.9]*

 Non-ADPKD

0.4 [0.2;0.6]*

1.0 [0.6;1.6]*

0.5 [0.2;1.0]*

0.7 [0.5;1.0]*

 Controls

0.7 [0.2;0.6]

2.1 [1.5;3.8]

1.5 [1.1;2.1]

1.4 [1.0; 2.2]

Kruskal-Wallis test

0.097

0.001

0.003

0.002