Assessment of Circulating Copeptin Levels in Healthy Subjects and Patients With Renal Insufficiency After Oral Water Load and Hypertonic Saline Infusion

The are 2 principal goals in this study:

1. To measure plasma copeptin levels in healthy subjects and to correlate them with plasma AVP concentrations and urine osmolalities in iso-, hypo-, and hyperosmolar states.
2. To measure plasma copeptin concentrations in patients with chronic renal failure under the same conditions described above, in order to characterize the impact of renal function on circulating copeptin levels in correlation to plasma AVP and urine osmolality.